Chapter One. A general introduction on feed resources in the coastal lowland Kenya, use of the legume tree forages, and their effect when used as supplements to low quality roughage is presented. This is followed by a review of the literature on the role of microbes in the rumen and the synthesis of microbial protein. The factors that influence the feed intake in ruminants are also reviewed. The role of the leguminous tree forages as supplements to low quality basal diet is presented with more emphasis on the effects of feeding forages from gliricidia and leucaena trees, on intake, digestion and animal productivity. The effects of deleterious compounds with particular reference to tannin is reviewed. Chapter Two. Twenty intact and five fistulated crossbred steers (Ayrshire/Brown Swiss x Sahiwal) were used in Experiment One. The materials and methods used in this experiment had much in common with those of the three following experiments. Therefore procedures similar to all experiments are described in this chapter and only briefly mentioned in the subsequent chapters. The objective of the experiment was to describe the response in production as a result of supplementing napier grass basal diet with incremental levels of gliricidia forage. Napier grass basal diet was offered ad libitum alone or supplemented with 7.5, 15, 22.5 or 30 g DM/kg W0.75/d. Intake and live weight changes were measured for 49 days, and digestibility, and microbial N supply during the last week of the experiment with the twenty steers, in a randomized design. The rumen parameters were measured in the five fistulated steers in a 5 x 5 latin square design. Total Dry matter (DM) intake tended to increase (5.2, 5.1, 5.2, 5.4 and 5.7 kg DM/d, s.e.d 0.21; P 0.05) with supplementation, but this was accompanied by a linear decrease in napier grass intake (5.2, 4.7, 4.5, 4.3 and 4.2 kg DM/d, s.e.d 0.21; P 0.05). The diet digestibility, rumen pH and in sacco DM degradation of napier grass remained unchanged, while the rumen ammonia concentrations (NH3-N) were increased linearly (P 0.05) from 130 to 215 mg/1 for control and highest level of gliricidia forage offered. When gliricidia was offered as proportionally 0.26 of the diet, animal weight gains were increased proportionally by about 0.56. The relationship between the amount of gliricidia offered and the average daily gain was such that, every 10 g DM /kg W0-75 increment of gliricidia forage resulted in 49 g/d of live weight gain. The estimated microbial N supply were lowest in the control group and supplementation tended to increase the yield, but with no significant difference across the treatments. Chapter Three. The objective of Experiment Two was to examine the effect of supplementing napier grass with incremental levels of leucaena forage on voluntary food intake, diet digestibility, rumen fermentation, and live weight gains in steers. The same animals used in Experiment One were used in this experiment. The levels of leucaena offered were 0, 7.5, 15, 22.5 or 30 gDM/kg W0.75/d, the same as those of gliricidia in Experiment One. Increasing the proportion of leucaena forage in the diet of steers offered napier grass had no significant effect on the intake of the napier grass (5.2, 5.3, 5.3, 5.3 and 5.0 kg DM/d, s.e.d. 0.21). The total DM intake increased linearly (5.2, 5.8,6.2,6.6 and 6.7 kg DM/d, s.e.d 0.31; P 0.001). The response was such that for every increment of 10 g DM/kg W0.75 of leucaena, the total intake was increased by 0.52 kg DM/d. Diet digestibility tended to increase, while the rumen pH and in sacco DM degradation characteristics remained unchanged with supplementation. Rumen NH3-N was significantly increased by approximately 11 mg/1 for every 10 g DM/kg W0.75/d of leucaena forage offered. The growth of the animals was improved with supplementation, and the relationship between the amount of leucaena in the diet and the gain was such that for every 10 g DM/kg W0-75/d increment of leucaena forage intake, the gains were increased by 96 g/d. It could be predicted that 1 kg of leucaena offered would result in 171 g/d of gain. At a highest level of leucaena offered ie. proportionally 0.27 of the diet, the weight gains were increased by 0.57 compared with the control group. Chapter Four. The objective of Experiment Three was to examine the effect of incremental levels of gliricidia forage on voluntary food intake, digestion, microbial N supply and live weight gains. Twenty crossbred steers (Ayrshire/Brown Swiss x Sahiwal) and five fistulated steers of the same breed were used for the trial. Intake, diet digestibility, microbial N supply and live- weight changes were measured using the twenty steers and the rumen parameters using the five fistulated steers. Maize stover was offered ad libitum plus 1 kg of maize bran alone, or supplemented with 7.5, 15, 22.5 or 30 g DM/kg W0.75/d of gliricidia forage. Supplementation with gliricidia forage significantly increased the total DM intake (3.0, 3.0, 3.2, 3.5, 3.5 kg DM/d, s.e.d. 0.10; P 0.001) but depressed the intake of maize stover. The response in total DMI was an additional of 0.21 kg DM/d for an increment of 10 g DM/kg W0.75 of the legume. Diet digestibility was not significantly changed, nor was the rumen pH. The degradation parameters was slightly higher in the supplemented group, however, there were no difference in the degradation characteristics of the feeds incubated in steers offered different level of legume forage. Rumen NH3-N and live weight gains were significantly increased with supplementation. The relationship between the proportion of the supplement in the diet and the rumen ammonia or daily gains were such that, for every increment of 10 g DM/kg W0 75 of the legume offered the NH3-N and daily gain were increased by 16 mg/1 and 69 g/d respectively. The microbial N supply tended to be higher in the supplemented groups than the control (30.8, 37.2, 32.9, 34.9, 32.3, s.e.d. 1.06; P 0.05). Chapter Five. Experiment Four compared the type (gliricidia or leucaena) and levels (15 or 30 g DM/kg W0.75) of legume forages given as supplements to maize stover. The effects on intake, diet digestibility, rumen parameters, microbial N supply and live weight gains are presented and discussed. The same steers used in Experiment Three were used in this experiment (Twenty for the growth trial, and the five fistulated animals for the measurements of rumen parameters. The steers were offered maize stover ad libitum plus 1 kg maize bran alone, (2 kg for the fistulated animals), or supplemented with either 15 or 30 g DM/kg W0.75/d of gliricidia or leucaena (Control, G15, G30, L15 or L30). The intake of the basal diet was significantly (P 0.05) increased from 2.3 to 2.5 and 2.3 to 2.7 kg DM/d when of either gliricidia or leucaena respectively were offered as 0.17 of the diet. At higher level of supplementation (to about 0.33 of diet), the maize stover intake tended to decline. The total DM intake were increased (P 0.001) at both levels of both supplements offered (3.2,4.1,4.6,4.3 and 4.6 DM/kg, s.e.d 0.05, being the intakes for control, G15, G30, L15 and L30 respectively). Supplementation at the lower level significantly increased the diet digestibility. The rumen pH remained unchanged, the rumen NH3-N increased (31, 80, 101, 95, 111 mg/1 s.e.d 20.4; P 0.001), and the in sacco DM characteristics of the feeds tended to increase with supplementation. Both the DM and nitrogen (N) in leucaena forage were degraded at a slower rate than in gliricidia. The control group had the lowest (P 0.001) gains, compared with the supplemented groups. The leucaena supplemented group tended to have higher live weight gains than the gliricidia group, but the differences were not significant. Gains were 81, 355, 695, 396, 753 g/d s.e.d 44.5 for control, G15, G30, L15 and L30 groups respectively. With all parameters measured, there were no significant difference between supplementation with gliricidia or leucaena forages, at either level.

The objective of the present work was to elucidate some of the possible choice determinants involved in diet selection by sheep and goats. The first experiment investigated the ingestive and digestive responses of these two species to a range of forage chemical composition attributes (i.e. nitrogen and fibre content). Forage DM intake was positively associated with their nutritive quality. Goats had higher voluntary DM intakes (P<0.05) and lower apparent digestibility coefficients (P<0.001) for any given forage than sheep, but the intake of digestible DM was similar for the two species. When forages were offered in pairs in a preference trial, the two species ranked forages similarly by favouring those of higher nutritive quality. The second experiment investigated the effects of different staple lengths of a single hay on the ingestive and digestive responses of sheep and goats. Goats had higher voluntary DM intakes (P<0.05) and lower apparent digestibility coefficients (P<0.001) for any given length than sheep, but the intake of digestible DM was similar for the two species. Goats allocated less time (P<0.001) than sheep to chewing the feed consumed and the mean retention time of the undigested residues in the animals' digestive tract was significantly shorter (P<0.01) for goats than sheep. When staple lengths of the grass hay were offered in pairs none of them was favoured and the choices were not significantly different between goats and sheep. In a third experiment a new method of feed presentation was developed and compared with conventional feed-bins. Goats had higher voluntary intakes than sheep (P<0.05), whereas there was no effect of the feed presentation method on DM intake.

The nutritional value of molassed sugar beet feed as a dietary component was assessed in a series of three experiments. In experiment 1, the effect of molassed sugar beet feed pellets (32 or 64 g/kg fresh weight silage) either ensiled or fed separately with big-bale silage on silage quality and performance of male castrate sheep (initial liveweight 29 kg) was studied. On average, the inclusion of molassed sugar beet feed increased silage dry matter, water soluble carbohydrate and lactic acid concentrations and decreased silage ammonia concentrations. Molassed sugar beet feed either ensiled or given as a supplement, significantly improved total dry matter intakes and liveweight gain (P< 0.05) and metabolisable energy intakes (P< 0.01) in lambs. Experiment 2 was carried out to investigate the effects of feeding two levels of fishmeal in addition to molassed sugar beet feed as supplements to big-bale grass silage fed ad libitum to beef steers of 290 kg initial liveweight. Bale silage was given alone or supplemented with 800 g molassed sugar beet feed/day, molassed sugar beet feed + 125 g fish meal/day or molassed sugar beet feed + 250 g fish meal/day. Supplementation of big-bale silage with molassed sugar beet feed did not increase total dry matter intake or improve liveweight gain. Adding FM to a diet composed of big-bale silage and molassed sugar beet feed significantly increased liveweight gain, total ruminal volatile fatty acid and ammonia concentrations. The effect of diets differing in the ratio of molassed sugar beet feed to barley and the inclusion of yeast culture on growth and rumen metabolism of sheep (initial liveweight 36 kg) was examined in experiment 3. Four diets, which were offered ad libitum , consisted of pelleted or molassed sugar beet feed, barley and soya-bean meal in the following proportions (DM basis) either A, 770:170:60 or B, 470:470:60. Diets A and B were fed with and without 2 g Yea-Sacc/head/day.

Call number: LD2668 .T4 1950 S654 / Master of Science

by Chan King Ming. / Bibliography: leaves 149-172 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1984

Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Michael D. Tokach / The dissertation consisted of 6 chapters involving studies in heavy weight market pig production, dietary Ca and P requirements for nursery pigs, antimicrobial resistance development in finishing pig microbiota, seasonal growth variability in commercial pig production, and leftover feed management in wean-to-finish pig productions. The first chapter presents a thorough review of published studies involving genetic selection, nutritional requirements, health, welfare, and pork quality of finishing pigs with marketing weight greater than 130 kg and assessed future research needs. Chapter 2 describes 2 experiments that evaluated the growth performance and percentage bone ash of early nursery pigs fed various combinations of Ca and P provided by inorganic sources or phytase. Feeding more than 0.90% dietary Ca decreased average daily gain (ADG), average daily feed intake (ADFI), gain:feed ratio (G:F), and percentage bone ash when diets were at or below NRC (2012) requirement for standardized total tract digestible (STTD) P. However, adding inorganic P or phytase to P deficient diets improved pig performance and alleviated the negative impacts of high dietary Ca concentration on growth performance. The experiment presented in chapter 3 characterized the dose-response to increasing digestible P in diets without or with 2,000 units of phytase for 6- to 13-kg pigs. Increasing STTD P from 80 to 140% of NRC (2012) requirement estimates in diets without phytase, and from 100 to 170% of NRC (2012) in diets with phytase, improved ADG, G:F, and percentage of bone ash. Estimated STTD P requirements varied depending on the response criteria and statistical models and ranged from 91 to >140% of NRC (2012) in diets without phytase, and from 116 to >170% of NRC (2012) for diets containing phytase. In addition, phytase exerted an extra-phosphoric effect on promoting pig growth and improved the P dose responses for ADG and G:F. In chapter 4, a study was conducted to determine the effects of tylosin administration route (through feed, drinking water, or intramuscular injection) on the growth performance and the development of antimicrobial resistance in fecal enterococci of finishing pigs. Pigs that received tylosin injection had decreased ADG and G:F compared with control pigs that did not receive any antibiotic treatment, which may be due to a stress response to the handling during injection administration. Moreover, tylosin administration via injection and feed resulted in a higher probability of enterococcal resistance to erythromycin and tylosin compared with drinking water treatment. Chapter 5 presents a retrospective analysis on the seasonal growth patterns of nursery and finishing pigs in 3 commercial production systems located in the Midwest US. Nursery ADG and ADFI expressed prominent seasonal variations and were similar among systems, whereas nursery G:F was not affected by season. Finisher ADG, ADFI, and G:F varied over seasons, but the magnitudes and patterns of change were system dependent. This chapter also presents the concepts underlying the implementation of a multi-level linear mixed model of production records to analyze seasonality and potentially other decision factors in commercial systems. Finally, in chapter 6, 2 experiments were conducted regarding the strategy of managing leftover finisher feed in a wean-to-finish production system. Experiment 1 evaluated the timing (phase) of feeding 2.5 kg/pig of finisher feed in a 5-phase nursery program. All growth responses decreased immediately when the finisher feed was blended into nursery diets; however, pigs greater than 11 kg (phase 3) had improved ability to compensate for the negative effects of finisher feed on overall growth performance. Experiment 2 was then carried out to investigate the maximum amount of finisher feed can be fed to 11-kg pigs. Increasing the finisher feed budget from 0 to 3.75 kg/pig resulted in a linear decrease in ADG and ADFI. However, the economic analysis indicated no change in income-over-feed-cost due to the timing and dose of blending finisher feed into nursery diets.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

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The objectives of this study were accomplished with two experiments in growing Bonsmara bulls (N = 68) (experiment 1), and Simmental crossbred calves (N = 132) (experiment 2). Specific objectives for experiment 1 were to characterize residual feed intake (RFI) in growing bulls, and examine relationships between RFI and performance, fertility, temperament and body composition traits. In experiment 2, the objectives were to examine stocker-phase supplementation effects on feedlot feed conversion ratio (FCR) and RFI and to characterize relationships between these feed efficiency traits, and performance and carcass traits in finishing calves. In both experiments, individual feed intakes and BW were measured. Ultrasound technology was used to measure body composition in experiment 1, while actual carcass measurements taken at harvest were used for experiment 2. Experiment 1 demonstrated that temperament affected ADG and DMI, but not FCR or RFI. Residual feed intake was not phenotypically correlated to scrotal circumference or bull fertility traits. Experiments 1 and 2 demonstrated that RFI was independent of ADG and BW, but that there was a tendency (P < 0.10) for RFI to be phenotypically correlated with 12th rib fat thickness (r = 0.20 and 0.22). However, RFI was not correlated with longissimus muscle area in either experiment. Both experiments demonstrated that low RFI (< 0.5 SD below mean RFI) calves consumed significantly (20 and 22%) less feed and had improved (21%) FCR compared to calves with high RFI (> 0.5 SD above mean RFI). Results from experiment 2 suggest that RFI measured while calves are consuming high-grain diets may be less influenced by previous level of stocker supplementation compared to FCR or residual gain efficiency traits. In summary, RFI was found to be phenotypically independent of growth rate and BW, had no effect on bull fertility or temperament traits, and was less impacted by previous plane of nutrition compared to FCR.