Typescript (photocopy). / Digitized by Kansas Correctional Industries

<p>Forty barrows were used in a 35d experiment to evaluate the effects of supplemental soluble fiber (dextrin) pre- and post-weaning on growth performance, intestinal microbiome, volatile fatty acid (VFA) production, intestinal morphology, and gene expression. Pigs were blocked by litter and BW, and randomly allotted to treatments in a 2x2 factorial design with or without fiber pre-weaning and with or without fiber post-weaning. Dextrin was administered orally through a syringe, after being suspended in chocolate milk from 14d prior to weaning through 3d post-weaning, after which it was included in the diet at 1%. At weaning, pigs were group housed by treatment and allowed ad libitum access to a common starter diet. On d4 post-weaning, pigs were moved to individual pens and fed diets with or without 1% fiber. Weights and feed intake were recorded 14 and 3d prior to weaning, and on d0, 4, 11, and 21 post-weaning. On d0 and d21 post-weaning, pigs were euthanized for collection of tissues and intestinal contents. Ileal, cecal, and colon contents were taken for microbiome analysis, distal large intestine contents were collected for VFA analysis, ileal cross sections were collected for histology, and ileal and cecal mucosal scrapings were collected for intestinal gene expression. Data were analyzed using the GLM procedure of SAS with pig as the experimental unit for growth performance, VFA production, intestinal morphology, and gene expression. Microbiome data were analyzed using Metastats, to find statistical significance between treatments, and then run through R, using the false discovery rate method, to find a multiple test corrections q-value. Growth performance in general was not affected (<i>P</i>> 0.10) by treatment with the exception of d11-21 feed efficiency was improved (<i>P</i>= 0.018) for pigs receiving supplemental fiber prior to weaning. Pigs that received fiber at any point had increased short chain fatty acid (SCFA) producing bacteria (<i>q </i>< 0.05) compared to pigs never receiving fiber. Pigs never receiving fiber had increased bacteria associated with intestinal inflammation (<i>q </i>< 0.05) compared to all other treatment groups. A trend for an interaction (<i>P </i>= 0.054) of pre- and post-weaning fiber supplementation<b></b>was observed for total volatile fatty acid concentration in large intestine contents. An interaction (<i>P </i>= 0.007) of pre- and post-weaning treatments was observed on butyrate, with pigs fed fiber only during pre-weaning having the greatest butyrate concentrations. Pigs fed fiber pre-weaning had decreased isobutyrate concentrations (<i>P </i>= 0.050) and percentages (<i>P</i>=0.040) and a trend for decreased isovalerate as a concentration (<i>P</i>= 0.058) and percent of total VFAs (<i>P </i>= 0.051). Pigs fed fiber post-weaning had increased acetate (<i>P </i>= 0.047). An interaction for butyrate percentages was observed with pigs receiving supplemental fiber only prior to weaning having the highest percent of butyrate (<i>P</i>= 0.029). An interaction for valerate concentrations (<i>P </i>= 0.045) occurred with pigs receiving fiber only prior to weaning having the highest amount of valerate. Valerate as a proportion of total VFAs (<i>P </i>= 0.038) was decreased in pigs receiving supplemental fiber post-weaning. Pigs fed fiber prior to weaning tended to have decreased crypt depths (<i>P </i>= 0.097) compared to pigs that did not receive fiber prior to weaning. In the ileum there was an interaction (<i>P </i>= 0.002) for GLP-2 expression, with pigs receiving supplemental fiber solely before or after weaning having the greatest expression. Occludin expression in the ileum tended to increase with fiber supplementation prior to weaning (<i>P</i>= 0.086) but then tended to decrease with fiber supplementation post-weaning (<i>P</i>= 0.053) In the cecum, there was an interaction (<i>P </i>= 0.049) of pre- and post-weaning fiber supplementation<b></b>on GLP-2 expression. Pigs fed supplemental fiber at any point had increased GLP-2 expression, but pigs that had fiber only after weaning had the greatest GLP-2 expression. Cecal HSP-70 expression also increased with fiber supplementation in pigs fed fiber post-weaning (<i>P </i>= 0.012). Soluble fiber supplementation caused alterations in the intestinal microbiome, VFA concentrations, the intestinal morphology, and in the expression of different intestinal genes.</p>

Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2010 / Ten experiments were conducted to determine the effect of dietary energy to protein ratio level on growth and productivity of indigenous Venda chickens raised in closed confinement from day-old up to thirteen weeks of age. The ten experiments were based on five different energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM. Each dietary energy level had five different levels of protein concentrations of 220, 190, 180, 170 and 160 g/kg DM, thus ending up with twenty five different dietary energy to protein ratio levels. Experiments 1 to 5 examined the effect of dietary energy to protein ratio on productivity of unsexed Venda chickens aged one to six weeks. Experiments 1 to 5 each commenced with 160 unsexed day-old indigenous Venda chicks with an initial weight of 25 ± 2 g per bird and each lasted for a period of six weeks. In each experiment, the chicks were randomly assigned to five treatments with four replications, each having eight birds. Thus, 20 floor pens (1.5 m2 /pen) were used in total for each experiment. All the five experiments were carried out around the same time. A complete randomized design was used for each experiment. A quadratic regression model was used to determine the ratios for optimum feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention in each experiment while a linear model was used to determine the relationship between optimal responses in the above variables and dietary energy to protein ratio levels. Dietary energy to protein ratio level for optimal response for any variable was relative and depended on the energy to protein ratio values of the diet. Energy to protein ratios of 63, 67, 70, 74 and 78 MJ ME/kg protein promoted optimal live weights of 415, 408, 370, 365 and 344 g at six weeks of age for diet energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM, respectively. However, optimal response trends for different variables were also influenced by the dietary energy to crude protein ratio. Optimal feed intake increased linearly with increasing dietary energy to protein ratio levels. Similarly, optimal metabolisable energy level increased linearly with increasing dietary energy to protein ratio levels without any increase in live weight. On the other hand, increasing dietary energy to protein ratio level decreased growth rate with a linear deteriorating feed conversion ratio,thus, negatively affecting live weight of the chickens at six weeks of age. However, increasing dietary energy to protein ratio levels improved efficiency of protein utilization with a linear deteriorating metabolisable energy utilization. In experiments 1 to 5, correlation analysis indicated that optimal feed intake, feed conversion ratio and metabolisable energy level were positively and strongly correlated with dietary energy to protein ratio levels while optimal live weight, growth rate and nitrogen retention were negatively and strongly correlated with dietary energy to protein ratio levels. The study indicated that a diet containing a crude protein content level of 178 g/kg DM and an energy level of 14 MJ ME/kg DM allowed for optimal utilization of absorbed protein and energy for growth in unsexed indigenous Venda chickens aged between one and six weeks. Experiments 6 to 10 examined the effect of dietary energy to protein ratio level on productivity of male Indigenous Venda chickens raised in closed confinement from seven up to 13 weeks of age. Each experiment commenced with 100 seven-week old male Venda chickens with an initial weight of 320 ± 2 g per bird. In each experiment, the chickens were randomly assigned to five treatments with four replications, each having five birds. Thus, 20 floor pens (1.5 m2/pen) were used in total for each experiment. All the five experiments were carried out around the same time and for a period of seven weeks. A complete randomized design wasused for each experiment. A quadratic regression model was used to determine energy to protein ratios for optimum feed intake, growth rate, feed conversion ratio,live weight, metabolisable energy, nitrogen retention, carcass yield, breast meatyield and fat pad deposition in each experiment while a linear model was used to determine the relationship between optimal responses of the above variables and dietary energy to protein ratio levels. Energy to protein ratios of 60, 71, 66, 72 and 71 MJ ME/kg protein promoted optimal live weights of 1167, 950, 983, 1235 and 1172 g at thirteen weeks of age for diet energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM, respectively. Optimal response trends in feed intake, growth rate, feed conversion ratio, nitrogen retention, and metabolisable energy intakes in male Venda chickens tended to increase with increase in dietary energy to protein ratio level. In contrast, optimal carcass and breast meat yield tended to decrease with increasing dietary energy to protein ratio level. However, optimal live weight and fat pad remained unchanged with increase in dietary energy to protein ratio value. Additionally, increasing dietary energy to protein ratio level improved efficiency of protein utilization with deteriorating metabolisable energy utilization.On the other hand, experiments 6 to 10 showed that optimal feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy level, nitrogen retention and fat pad were positively and poorly correlated with dietary energy to protein ratio levels while optimal carcass weight and breast meat yield were negatively and poorly correlated with dietary energy to protein ratio levels This study indicated that a diet containing 193 g CP/kg DM and an energy level of 14 MJ ME/kg DM allowed for optimal utilization of absorbed protein and energy for growth in male indigenous Venda chickens aged between seven and thirteen weeks.It is, therefore, concluded that optimal response trends for different variables in growing unsexed Venda chickens offered diets differing in optimal dietary energy to protein ratio levels are influenced by the diet crude protein content rather than the feed energy level per se. Diets containing decreased dietary energy to protein ratio levels may promote improved growth rate and efficient feed conversion ratio while naturally restricting feed intake. Diets containing increased dietary energy to protein ratio levels favoured efficient utilization of consumed dietary protein. However, with such diets, protein became limiting and birds increased their feed intake attempting thereby to obtain more of the limiting protein in order to meet their protein requirement regardless of the energy value of the diet.It is, also, concluded that growing male Venda chickens increased their feed intake with increase in dietary energy to protein ratio. This is contrary to what has been observed in broiler chickens which decrease their intake with increase in diet energy value. It is suggested that this might reflect the differences between indigenous and broiler chickens in terms of their genetic and physiological abilities to regulate their feed intakes according to dietary energy levels. / National Research Foundation (NRF)

Thesis (Ph.D.) --University of Limpopo, 2012 / A series of experiments were carried out to evaluate the feeding values of forage sorghum (Sorghum sudanense), cowpea (Vigna ungiculata), lablab (Lablab purpureus) and mucuna (Mucuna pruriens) hays for Pedi goat production in Limpopo Province, South Africa. The first study determined nutrient composition and tannin contents of the forages. The experimental design was a completely randomised design with four treatments: forage sorghum, cowpea, lablab and mucuna hays. All the legume species had higher (P<0.05) protein contents than sorghum hay, ranging from 18 to 22 %. Within the legume species, cowpea hay had a higher (P<0.05) protein content than lablab and mucuna hays. Similarly, lablab hay had a higher (P<0.05) protein content than mucuna hay. Mucuna hay had a higher (P<0.05) concentration of both condensed tannins and hydrolysable tannins than cowpea, lablab and sorghum hays, while lablab hay had the highest (P<0.05) concentration of total polyphenols. The second study determined relative palatability indices of Pedi goats offered forage sorghum, cowpea, lablab and mucuna hays. Four male Pedi goats aged five months and weighing an average of 18 + 2 kg were used. The experimental design was a completely randomized design, with feeds (forage sorghum, cowpea, lablab and mucuna) as treatments and individual animals as replicates. Lablab and mucuna legumes had higher (P<0.05) intake and palatability indices than sorghum and cowpea hays. Palatability indices were positively and significantly (P<0.05) predicted from dry matter intakes of goats (r2 = 0.98). However, there were poor and non-significant (P>0.05) relationships between nutrient contents of the forages and their intake and palatability indices by goats. The third study determined diet intake, digestibility and live weight gain of seven months old Pedi goats fed a basal diet of forage sorghum supplemented with different amounts of cowpea, lablab or mucuna hays. The experimental design was a completely randomized design, with individual animals placed in digestibility crates as experimental units. This study was divided into a series of experiments due to lack of equipment to conduct the whole experiment in one session. A total of four experiments were conducted. Fifteen growing male Pedi goats were used in each experiment, with mean live weights of 15 + 4 kg, 18 + 2 kg, 17 + 3 kg and 20 + 4 kg for experiments 5.1, 5.2, 5.3 and 5.4, respectively. In each experiment, different goats were used. Experiments 5.1 to 5.3 involved cowpea, lablab and mucuna hays, respectively, while Experiment 5.4 compared the levels of supplementation for optimum intake from each of the first three experiments. Dry matter intakes of cowpea and lablab hay were optimised at 39 and 32 %, respectively, while that of mucuna hay increased with increasing levels of mucuna hay supplementation. Dry matter digestibilities of cowpea, lablab and mucuna hays increased with increasing levels of the respective forage supplementations. Cowpea and mucuna hay supplementations improved (P<0.05) final live weights and feed conversion ratios, while goats on lablab hay supplementation lost weight. At optimum intake, goats supplemented with mucuna hay had a better (P<0.05) feed conversion ratio than those supplemented with lablab and cowpea hays. The fourth study determined in vitro gas production of pure and mixtures of forage sorghum with cowpea, lablab and mucuna hays. Two experiments were conducted. In the first experiment (Experiment 6.1) the experimental design was a completely randomised design with four treatments (forage sorghum, cowpea, lablab and mucuna). The legume species of cowpea, lablab and mucuna hays produced more (P<0.05) gas than sorghum hay after 12 hours of incubation. Sorghum hay produced more (P<0.05) gas than cowpea, lablab and sorghum hays after 24, 48 and 72 hours of incubation. Sorghum hay dry matter intake by goats in the palatability trial was positively and significantly (P<0.05) predicted from gas production after 12 (r2 = 0.99), 24 (r2 = 0.97) and 48 (r2 = 0.93) hours of incubation. Cowpea hay, lablab hay and mucuna hay dry matter intakes by goats were poorly predicted from gas production after 12, 24, 48 and 72 hours of incubation. In the second experiment (Experiment 6.2), the experimental design was a completely randomised design with three treatments (mixtures at optimum intake): 1. FS61C39: A mixture of 61 % forage sorghum and 39 % cowpea, 2. FS68L32: A mixture of 68 % forage sorghum and 32 % lablab, 3. FS77M23: A mixture of 77 % forage sorghum and 23 % mucuna. There were no differences in gas production (P>0.05) across dietary mixtures after 12, 24, 48 and 72 hours of incubation. Dry matter intake by Pedi goats of sorghum hay mixed with cowpea at 39 % hay was positively and significantly (P<0.05) predicted from gas production of the mixtures after 24 hours (r2 = 1.0) of incubation. Dry matter intake from gas production from the same mixture was poorly predicted from gas production after 48 (r2 = 0.45) and 72 (r2 = 0.13) hours of incubation. Dry matter intake of sorghum hay by Pedi goats supplemented with lablab hay at 32 % was moderately predicted from gas production after 48 (r2 = 0.67) and 72 (r2 = 0.60) hours, but poorly predicted after 12 (r2 = 0.50), 24 (r2 = 0.53) hours of incubation. Dry matter intake of sorghum hay by Pedi goats supplemented with 23 % mucuna hay was positively predicted from gas production after 12 (r2 = 0.90) hours, but moderately predicted after 24 (r2 = 0.80), 48 (r2 = 0.72) and 72 (r2 = 0.83) hours of incubation. Dry matter digestibility of sorghum hay mixed with 23 % mucuna hay was positively and significantly (P<0.05) predicted from gas production after 24 (r2 = 1.0), 48 (r2 = 0.99) and 72 (r2 = 1.0) hours of incubation. Dry matter digestibility of sorghum hay mixed with 39 % cowpea hay was positively predicted from gas production after 48 (r2 = 0.95), moderately predicted after 24 and 72, and poorly predicted after 12 hours of incubation. Dry matter digestibility of sorghum hay mixed with 32 % lablab hay was positively predicted from gas production after 72 (r2 = 0.92) hours of incubation. The relationships between digestibility of the mixtures and gas production after 12, 24 and 48 hours of incubation were poor. The fifth study determined in sacco degradation of mixtures at optimum intake of forage sorghum mixed with cowpea, lablab or mucuna when incubated in goats. The ‘a’ values and dry matter losses in cowpea and lablab hays were higher (P < 0.05) than those of mucuna hay. Dry matter intake of sorghum hay mixed with lablab hay at 32 % was positively and strongly predicted from in sacco degradation after 12 (r2 = 0.90), 24 (r2 = 0.94), 48 (r2 = 0.96) and 72 (r2 = 0.97) hours of incubation. Dry matter intake of sorghum hay mixed with 39 % cowpea hay was poorly predicted from in sacco degradation after 12 (r2 = 0.25), 24 (r2 = 0.20), 48 (r2 = 0.11) and 72 (r2 = 0.08) hours of incubation. Dry matter intake of sorghum hay mixed with 23 % mucuna hay was positively and moderately predicted from in sacco degradation after 12 (r2 = 0.68) hours and 24 (r2 = 0.55) hours, but poorly predicted after 48 (r2 = 0.40) and 72 (r2 = 0.20) hours of incubation. vii It was concluded that cowpea, lablab and mucuna hays had higher protein contents and palatability indices than forage sorghum and therefore, have the potential of being utilised as protein supplements for goats on low quality roughages. Legume supplementation, in general, improved diet intake, digestibility, feed conversion ratio and live weight of goats, except for lablab hay supplementation. It was also noted that diet intake, digestibility and final live weights of the goats were optimised at different levels of forage supplementation. This may indicate that supplementation levels for optimum productivity will depend on the particular parameter in question. In vitro gas production and in sacco degradation techniques have the potential of predicting intake, digestibility and palatability indices of goats fed sorghum hay supplemented with cowpea, lablab or mucuna hays.

Orientador: Luciano Hauschild / Coorientador: Paulo Henrique Reis Furtado Campos / Banca: Alex Sandro Campos Maia / Banca: Urbano dos Santos Ruiz / Resumo: Objetivou-se com esse estudo avaliar o sistema de alimentação sequencial como uma ferramenta para atenuar os efeitos do estresse cíclico por calor em suínos de duas linhagens genéticas nas fases de crescimento e terminação. Oitenta suínos machos castrados de 22kg (± 2,5) PV foram distribuídos em um delineamento experimental inteiramente casualizado, em esquema fatorial 3x2 (3 programas de alimentação e 2 linhagens genéticas; 3 PA e 2 LG) sendo o animal a unidade experimental. Os PA foram: Controle (CON), alta-gordura/baixa-proteína bruta (AG/BP) e Alimentação Sequencial [SEQ, de 1800 às 1000 h dieta controle (Tempo-Período 1, TP1) e de 1000 às 1800 h dieta AG/BP (TP2)]. A temperatura foi 22.3 ± 0.4ºC para TP1 e 30.2 ± 0.5ºC para TP2. A duração do período experimental foi de 84 dias subdividido em três fases: crescimento 1 (0 a 20 dias), crescimento 2 (21 a 48 dias) e terminação (49 a 83 dias). O consumo de ração foi registrado em tempo real pelo sistema automático de alimentação (AIPF). Os animais foram pesados no início e no término de cada fase experimental e nos dias 0, 35 e 75 foi mensurada a composição corporal. Houve interação entre LG e Tempo-Período (TP) para consumo médio de ração (CMR) por hora (P < 0,05). A 22ºC o CMR não se diferiu entre linhagens (P > 0,05) contudo, a 30ºC foi maior para linha B (P < 0,05). Houve interação (P < 0,05) entre PA e LG para custo energético de ganho de massa magra. De 35 a 75 dias, SEQ apresentou similar custo para ganho de massa magr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed at evaluating the sequential feeding system as a tool to attenuate the effects of cyclic heat stress in two genetics of growing-finishing pigs. Eighty 22kg (± 2.5) BW barrows were assigned in a completely randomized experimental design, in factorial scheme 3x2 (3 feeding programs and 2 genetic lines; 3FP and 2GL) being the animal the experimental unit. The FP were: Control (CON), high-fat/low-crude protein (HF/LP) and Sequential Feeding [SEQ, from 1800 to 1000 h control diet (Time-Period 1, TP1) and from 1000 to 1800 h HF/LP diet (TP2)]. The temperature was 22.3 ± 0.4ºC for TP1 and 30.2 ± 0.5ºC for TP2. The experimental period lasted 84 days subdivided into three phases, growing 1 (0 to 20d), growing 2 (21 to 48d), and finishing phase (49 to 83d). Feed intake was recorded using Automated Feeder System. Pigs were weighed at beginning and end of each experimental phase and on days 0, 35 and 75 were measured the body composition. There was interaction between GL and time-period (TP) for average feed intake (AFI) per hour (P < 0.05). At 22ºC the AFI did not differ between lines (P > 0.05), but at 30ºC the line B pigs had higher values than line A (P < 0.05). There was interaction (P < 0.05) between FP and GL for energy cost of lean gain. From 35 to 75d, SEQ had similar energy cost of lean gain for line A compared to CON (P > 0.05). However, for both lines, SEQ had higher the energy cost of lean than CON (P < 0.05). In growing 1 e 2 there was not difference (P > 0... (Complete abstract click electronic access below) / Mestre

Corrigenda inserted behind title page. Copies of author's previously published articles inserted. Bibliography: leaves 193-210. This study investigated whether estrogen could modulate the proteins associated with calcium transport (eg calcium binding protein, calbindin D28k) in the intestinal tissue during sexual maturation of laying hens. The first study investigated the temporal and spatial expression of estrogen receptors (ER) and calcium binding protein in jejunal tissue. Findings indicated the potential of estrogen to induce calbindin D28K in the intestinal tissue, from which it can be concluded that estrogen may increase calcium absorption and consequently calcium retention. It was shown that the amount of estrogen normally present in the reproductive system is sufficient for the normal capacity of egg and eggshell production. Egg production and shell quality were significantly reduced by phytoestrogen. It is recommended that the concentration of phytoestrogen in poultry diets be investigated in more detail as it may act as an anti-nutritive factor and affect metabolism and productivity.

A field study was conducted to assess phosphorus (P) and potassium (K) concentrations of both lactating and dry cow diets on Oregon's dairies. Thirty-seven dairy farms, located in western Oregon, were grouped according to geographic region, valley (V) or coast (C), and herd size, small (S) or large (L). Farms were visited on three separate occasions. During each visit, lactating and dry cow diets were recorded and corresponding feed ingredients were collected and analyzed for P and K. For each diet recorded, fecal and urine samples were collected and analyzed for P and K. When available, milk production data was obtained. During the initial visit, a survey was issued to producers to assess P and K knowledge as well as gather herd data and management information. Survey responses received indicated that two-thirds of participants were knowledgeable about P and its affects within the environment. Knowledge of K appeared to be less than that of P. Average P concentration of the lactating cow diet was 0.40% (DM basis) and did not differ between region (P=0.12) or herd size (P=0.76). Fecal P excretion did not differ between region (P=0.08) or herd size (P=0.27), however, a trend for larger fecal excretion in V farms contributed to the lower calculated apparent P digestibility for V than C. Potassium in lactating cow diet was greater (P=0.01) for C than V, however, but no difference between herd size (P=0.10) was determined. Overfeeding of K also occurred in dry cow diet with no difference between region (P=0.40) and herd size (P=0.72). Combining the fecal and urinary fractions, an individual lactating cow consuming 0.40% P (89.8 g) and 1.71% K (384.3 g) per day will excrete 24.0 kg of manure P and 76.3 kg of manure K annually. The magnitude of plant available P and K produced; requires Oregon producers to acquire additional land, an additional two-tenths ha/cow, to be to apply P and K at agronomic rates. / Graduation date: 2004

Three experiments were conducted to evaluate the influence of quality of supplemental alfalfa quality on beef cattle consuming low-quality meadow grass (MG) roughages. Fifteen steers (250 kg) were assigned randomly to one of three treatments: 1) meadow grass (5.2% CP), no supplement (MNS); 2) meadow grass plus high quality alfalfa hay (AHS) (18.8% CP); and 3) meadow grass plus low quality alfalfa hay (ALS) (15.2% CP). Supplements were fed at 0.45% BW and 0.55 % BW respectively. Total DM intake was greater (P<.01) for alfalfa supplemented steers. Likewise intake of digestible DM, DM digestibility and ruminal ammonia levels were greater for alfalfa supplemented steers (P<.01). In Exp. 2; 96 gestating Hereford x Simmental cows (537 kg; body condition 4.86) were assigned to the same treatments as in Exp. 1. For d-0 to d-42 cows grazed on 19.1 ha of stockpiled MG (4539 kg/ha; 6.8% CP) whereas d-43 to d-84, cows received MG hay (5.2% CP). Results for the 84-d study indicated that supplemented cows gained more BW (P<.01), body condition (P<.01) and had heavier (P<.01) calf birth weights than MNS cows. In the first 42-d period supplemented cows gained 16.2 kg more BW than MNS cows (P<.01). Likewise, supplemented cows increased .24 BC more (P<.01) than MNS cows. The same trend was observed from d-42 to d-84, though ALS cows lost more BC (P<.01) than the AHS cows. In Exp. 3; 90 gestating Angus x Hereford cows (475 kg; body condition 4.59) were assigned to one of three supplemental treatments: 1) 16.1% CP alfalfa; 2) 17.8% CP alfalfa; 3) 20.0% CP alfalfa. The level of supplementation was 0.63%, 0.55%, and 0.50% of BW, respectively. The basal diet was baled MG hay (5.6% CP). Weight gain and BC change for the 84-d study displayed a quadratic response (P<.10). In conclusion, alfalfa hay is an effective way of increasing low-quality roughage DM intake and digestibility. However, alfalfa hay quality did not appear to dramatically effect BW, BC, and (or) calf birth weights, when fed on a isonitrogenous basis. (KEY WORDS: Beef cattle, Supplementation, Meadow Hay, Alfalfa Hay) / Graduation date: 1997

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 172-181).

Two studies were conducted to determine the effects of zinc (Zn), copper (Cu) and/or selenium (Se) on the humoral immune response of weaned steers fed diets deficient in these minerals. Steers were bled weekly for eight weeks to measure plasma mineral levels. Humoral immune response was measured as antibody response to Keyhole limpet hemocyanin (KLH) over seven weeks of the trials. Steers were injected with 0.5 ml KLH vaccine on weeks 2 and 5 of the Zn study. Ten steers (5 per treatment) were randomly assigned to either a Zn supplemented (z), 3.25 ml injectable zinc-oxide suspension (100 mg/ml oil) or a control (c) treatment. Plasma Zn was maintained at higher (P<.05) levels in supplemented steers from week 3 through week 8. Humoral immune response was not different (P>.10) between treatments. In 1988, 20 steers were stratified by weaning weight and randomly assigned to one of four treatments: 1) Injectable Se 1 ml Mu-Se/ 90.9 kg body weight, 2) Injectable Molycu 2 ml, 3) control, or 4) Se + Cu. Plasma Cu was higher (P<.05) in treatments 2 and 4 from week 2 through 8. Steers were injected with 0.5 ml of KLH vaccine on weeks 2 and 6. Immune response was not different (P>.10) between Cu supplemented steers and other treatments. Plasma Se was higher (P<.05) in treatment 1 as compared to 2 and 3, but not different (P>.10) from 4. Immune response was highest (P<.05) in treatment 1 with others not different(P>.10). In 1990, a second trial was conducted with 48 steers stratified by weight and randomly assigned to one of the same four treatments. Plasma Cu was higher (P<.05) on week 3 for both groups receiving Cu. Plasma Se was higher (P<.05) on weeks 2 through 5 for both groups receiving Se. Humoral immune response was higher (P<.05) on weeks 7 and 8 for both groups receiving Se. Humoral immune response was uneffected by Zn status of weaned beef steers. Selenium had a positive effect and Cu had no effect on humoral immune response of weaned beef steers. Copper also tended (P=.07) to reduce the positive response from Se. / Graduation date: 1991