The aim of this study was to determine whether a rapid release N source can be substituted with a slow release N source without having any negative effects on intake, digestibility, rumen fermentation and microbial protein synthesis, if sheep are fed a poor quality roughage. Five rumen cannulated wethers were used in the trial in a 5x5 latin square design. Cannulated wethers were assigned to different treatments after each experimental period. The treatments studied had different proportions of urea to OptigenrII, with the same inclusion level of starch and a mineral premix between treatments. The five different treatments were: 100% urea; 75% urea:25% OptigenrII; 50% urea:50% OptigenrII; 25% urea:75% OptigenrII and 100% OptigenrII. Significant differences (P<0.05) between the 25% urea:75% OptigenrII and the other treatments in terms of intake suggested that a combination of urea and OptigenrII might be the preferred supplementation due to a significantly higher dry matter intake (DMI), organic matter intake (OMI), neutral detergent fibre intake (NDF intake) and digestible organic matter intake (DOMI). The intake variables of 100% urea and 100% OptigenrII did not differ (p>0.05). No differences (P>0.05) were recorded for dry matter digestibility (DMD), organic matter digestibility (OMD) and neutral detergent fibre (NDF) digestibility between treatments. However, the 100% OptigenrII treatment had a significant (P<0.05) lower apparent nitrogen digestibility, which might be the result of a slower rumen NH3-N release and higher nitrogen excretion than the other treatments. No differences were observed for pH and VFA between different treatments. The rumen NH3-N concentration of the 100% OptigenrII treatment was significantly (P<0.05) lower than the 100% urea treatment at 2 and 4 hours after infusion. The effective degradability of both DM and NDF did not differ (P>0.05) between treatments. Neither were there differences between treatments for total microbial crude nitrogen (MCN) production. Based on biological evaluation, it could be suggested that urea might be substituted with OptigenrII in supplements. From an economical point of view, urea might still be the preferred NPN source, as urea is cheaper than OptigenrII in terms of R/kg nitrogen. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Animal and Wildlife Sciences / unrestricted

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20416号 / 農博第2201号 / 新制||農||1047(附属図書館) / 学位論文||H29||N5037(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 稲村 達也, 教授 白岩 立彦, 教授 廣岡 博之 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

No description available.

Doctor of Philosophy / Department of Animal Sciences and Industry / James S. Drouillard / A series of studies were conducted to evaluate extrusion processing of finishing diets on growth performance, carcass characteristics, and meat quality attributes of feedlot cattle. Extruded diets were processed in a 24:1 (length/diameter) corotating, fully intermeshing twinscrew extruder (model BCTG-62, Bühler AG CH-9240, Uzwil, Switzerland). In Experiment 1, extrusion processing of corn based diets decreased dry matter intake (DMI) and improved gain efficiency (G:F) by 15% compared to heifers fed steam-flaked corn (SFC) diets. Carcass characteristics were not different between treatments. Steaks from heifers fed SFC diets were juicier and had a less pronounced off-flavor than steaks from heifers fed extruded diets. In Experiment 2, average daily gain (ADG), DMI, G:F, carcass characteristics, and meat quality attributes were not different between heifers fed SFC and extruded processed corn diets. In Experiment 3, we evaluated different degrees of extrusion processing by altering the level of process water added to the extruder. Mechanical energy inputs, die pressure, die temperature, and torque of drive motor decreased as the level of water added to the extruder increased from 4% to 12%. Water addition did not affect DMI or ADG of feedlot heifers. However, live body weight (BW) and G:F decreased as the level of process water increased. Gain efficiency (carcass-adjusted basis) was 3% greater for extruded corn diets processed with 4% water compared with SFC diets and was 6% poorer than SFC diets when processed with 12% water. Apparent total tract digestibility was not different, but IVDMD improved with increasing levels of water. Improvements in G:F when fed extruded feed was variable among the 3 studies. This may be due, in part to severe infestation by European Starlings during Experiment 1. Impact of feed depredation by starlings was therefore evaluated. Starlings consumed 86% of the SFC diet offered to them compared to, none of the extruded corn diets. In addition, starlings preferentially selected for the energy dense portion of the rations (steam-flaked corn). Therefore, it is plausible that a portion of the 15% improvement in G:F observed in Experiment 1 for heifers fed extruded corn diets can be attributed to differences in feed depredation by starlings. Finally, two studies were conducted to evaluate extrusion processing of sorghum-based diets. In the first experiment, DMI was greater and G:F was poorer for heifers fed extruded sorghum diets compared to heifers fed steam-flaked sorghum (SFS) diets. However, carcass characteristics and meat quality attributes were not different. In the second study, particle size of the ground sorghum added to the extruder was evaluated. Processing sorghum to a smaller particle size (581 μm) prior to extrusion processing decreased DMI, improved G:F, and increased apparent total tract digestibility compared with larger particle sizes (1,264 μm). However, heifers fed SFS diets were still more efficient that heifers fed extruded diets made with either particle size of sorghum. Overall, this research suggests that extruding complete diets into homogeneous pellets may improve G:F of cattle fed corn-based diets while reducing feed depredation of starlings. It is also clear from our results that G:F is improved to a greater extent to processing diets under high shear conditions (i.e., high mechanical energy inputs) than when processed under low shear conditions.

Doctor of Philosophy / Department of Animal Sciences and Industry / J. S. Drouillard / Four experiments were conducted to evaluate the potential for accelerating adaption to high-concentrate diets and improving the health of high-risk calves, by administering an oral dose of Megasphaera elsdenii. Lactipro, a probiotic containing a live culture of Megasphaera elsdenii (10[superscript]9 CFU/mL), was orally dosed to cattle (100 mL) at initial processing. In experiment 1, heifers were adapted to a high-concentrate diet in 21 d without Lactipro or dosed with Lactipro and adapted in 16 d, 11 d, 6 d, or fed the high-concentrate diet d 1. Accelerating adaptation decreased DMI (P = 0.09), ADG, and efficiency (P < 0.05) during the first 30 d compared to cattle adapted over 21 d. Over 129 d, DMI and ADG were not different (P ≥ 0.12), but efficiency tended (P = 0.08) to be better for cattle adapted over 21 d. Liver abscesses and carcass traits were not different between treatments, with the exceptions of LM area (quadratic, P < 0.01) and marbling (linear, P = 0.07), which tended to increase with accelerated adaptation protocols. In experiment 2, cattle dosed with Lactipro and placed directly onto the finishing diet required less roughage (P < 0.01), tended to have lower DMI (P = 0.07), better quality grade (P ≤ 0.07), and similar ADG and efficiency (P ≥ 0.14) compared to cattle adapted over 18 d without Lactipro. Over the first 24 d DMI, DM fecal output, and apparent total tract NDF digestibility were greater (P < 0.01) for cattle adapted over 18 d. In Experiment 3, dosing calves, of Mexican origin, with Lactipro did not affect performance (P ≥ 0.16). Second antibiotic therapies for undifferentiated bovine respiratory disease (UBRD) tended (P = 0.06) to be lower in calves dosed Lactipro. In Experiment 4, dosing calves from Texas with Lactipro increased DMI, ADG, and efficiency (P ≤ 0.05). The incidence of 1st and 2nd antibiotic therapies for UBRD (P < 0.01) and medical cost were decreased for calves dosed Lactipro (P < 0.05). Dosing cattle with Lactipro allows for accelerated adaption to high-concentrate diets, decreases reliance on roughages, and improves health during the receiving period.

A high moisture corn/soybean meal-based finishing ration was used to examine the effects of roughage source (corn silage, alfalfa hay), level of dietary roughage (8, 16, 24%), and ractopamine supplementation (none, Optaflexx) on growth performance, carcass traits, and beef quality for finishing 108 steers and 24 heifers (initial BW = 308 kg). Cattle were allocated by gender to 12 management regimen subclasses. Optaflexx (trade name for ractopamine hydrochloride) was fed over the last 28 d on feed with cattle marketed after common days on feed. Growth performance (ADG, feed intake, and feed efficiency) and carcass traits were assessed on an individual animal basis. A primal rib and semitendinosus (ST) muscle from each animal were processed at the University of Guelph Meat Laboratory for carcass and meat quality evaluations. Tenderness was determined using shear force assessment of product aged 7, 14, and 21 d. Average daily gains were similar (P > 0.27) across main effects while use of corn silage as the roughage source decreased (P < 0.001) dry matter intake and improved (P < 0.001) feed efficiency compared to feeding alfalfa hay. Roughage level and beta agonist supplementation did not affect (P > 0.13) dry matter intake or feed efficiency. When the last 28 days on feed were examined, Optaflexx supplementation increased (P < 0.001) weight change, ADG, and improved feed conversion, while DMI remained unchanged (P > 0.373). Carcass traits including hot carcass weight, grade fat, longissimus muscle area, marbling, and body composition as assessed by rib dissection (% lean, fat, bone) were not affected (P > 0.14) by roughage level, source, or use of Optaflexx. Fat partitioning and liver abscess scores were unaffected (P > 0.09) by source and level of roughage fed, and use of Optaflexx. Source and level of dietary roughage did not affect color (P > 0.21) or shear force (P > 0.20) values for longissimus (LM) and semitendinosus (ST) steaks. Lower DMI and better feed conversion can be achieved using corn silage as the roughage source, while inclusion of up to 24% roughage in finishing diets may not negatively impact gains, carcass characteristics or beef quality. Beef producers may be able to increase amounts of roughage in the diet to lower cost of production without compromising growth performance and carcass and meat quality.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective was to evaluate concentrate substitution by corn silage on steers performance, as well as carcass and meat characteristics. The animals were organized according to the following treatments: 0% Sil: supplementation with 100% of corn grain; 33% Sil: supplementation with 66% of corn grain and 33% of corn silage; 50% Sil: supplementation with 50% of corn grain and 50% of corn silage; 66% Sil: supplementation with 33% of corn grain and 66% of corn silage; 100% Sil: supplementation with 100% of corn silage. The animals were slaughtered with average weight and body condition of 426.1 kg and 3.21 points, respectively. No significant interaction was observed between treatments and periods for forage mass, daily weight gain and stoking rate. The average forage mass was increased with the inclusion of roughage as supplement, providing higher stoking rate. The daily weight gain, weight gain per area and body condition didn t differ between treatments (P>.05). Treatments 66% Sil and 100% Sil had presented minor carcass length. Also significant correlation between amount of muscle and bone was verified (P= 0,0012 and r=0,67). Carcass and meat characteristics didn t show significant variations that can infer problems in animal commercialization. / O objetivo do experimento foi avaliar a substituição do concentrado pela silagem de milho no desempenho de novilhos de corte, bem como na carcaça e na carne. Os animais foram organizados de acordo com os seguintes tratamentos: 0% Sil: suplementação com 100% de grão de milho; 33% Sil: suplementação com 66% de grão de milho e 33% de silagem de milho; 50% Sil: suplementação com 50% de grão de milho e 50% de silagem de milho; 66% Sil: suplementação com 33% de grão de milho e 66% de silagem de milho; 100% Sil: suplementação com 100% de silagem de milho. Os novilhos foram abatidos com peso médio e escore corporal de 426,1 kg e 3,21 pontos, respectivamente. Houve interação significativa entre tratamentos e período para as variáveis massas de forragem (MF), taxa de crescimento diário (TC) e carga animal (CA) e peso final. A MF média foi superior frente aos tratamentos com maior inclusão de volumoso suplementar à dieta, principalmente com relação ao 100% Sil, promovendo, assim, aumento na CA para os mesmos. O ganho de peso médio diário, o ganho de peso vivo por hectare e o escore corporal não apresentaram variação significativa entre tratamentos (P>0,05). Os tratamentos 66% Sil e 100% Sil apresentaram menor comprimento de carcaça. Também foi verificada correlação significativa entre quantidade de músculo e osso (P= 0,0012 e r=0,67). Contudo não houve variações significativas que possam inferir problemas no momento da comercialização dos animais junto aos frigoríficos.

In the ZD Kojčice cooperative farm, a stable in Krasíkovice was studied in 2013 and 2014. The farm's production technology and the quality of the ensiled feed, feeding techniques, composition of the feed portions and selected milk production indicators were examined. The economy of milk production was also assessed. The production of ensilage ensured quality feed that was the basis for the milk cows' feed portions. The results show that the feed portions were well balanced in comparison to the recommended nutritional values for milk cows. The average yield in 2014, unlike 2013, decreased by 146 l to 5 960 l per milk cow per year. The costs per feed day were established at 138,2 Kč. The average costs for one liter of milk were 8,75 Kč/l.

In the Czech Republic, the grasslands constitute an important landscape element and at the same time, they are one of the basic components of horses' and ruminants' rations. Therefore, the fodder quality is important in the connection with production functions of grassland forage, especially concerning the dairy cattle. The aim of the diploma thesis was to monitor changes in the nutritional value during the vegetation and the evaluation of quality indications for selected species of Cock's-foot: three existing varieties and three varieties of the new breeding. Ash, crude protein, spectra fiber, organic matter digestibility index and relative feed value were evaluated. The changes between different phases of the vegetation were identified by raising proportion of CF, ADF and NDF in all varieties analyzed. During the aging of the cover, this process corresponded to deteriorating organic matter digestibility, decreasing relative feeding value and a decreasing tendency of nitrogen compounds. The value of CF in increasing in average from 22.6% up to 28.5%, NDF is increasing from 53.4% up to 60.5% and ADF from 29.3% up to 36.8 %. The digestibility of the organic value decreased from an average of 73.8% to 63.12%. Relative feed value decreased from an average of 114 to 91. During the vegetation, crude protein content also decreased from an average of 15.3% to 8.8%. From the analysis of results we can deduce that the varieties Vega are the best quality, vv115/10 and vv88/10, being nutritionally well balanced. The variety Zora is the worse quality. In terms of digestibility and relative feed values, the varieties of the new breeding are higher quality. These varieties are better with respect to the digestibility and relative feeding value than already existing varieties of Cock's-foot.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of the present study was to evaluate the effect of diet substitution of maize silage by sunflower silage on performance and ingestive behavior of feedlot steers. Nine steers, with average initial live weight and age of 288 kg and 20 months, respectively, from Nellore (N), 21/32Charolais (C) 11/32N and 21/32N 11/32C genetic groups, were used. The tested diets were: SG0= roughage with 100% of maize silage and 0% of sunflower silage; SG33= roughage with 67% of maize silage and 33% of sunflower silage and SG66= roughage of 34% of maize silage and 66% of sunflower silage. For all diets, the roughage:concentrate ratio used was of 60:40. The substitution of maize silage by sunflower silage didn t influence (P>.05) dry matter, neutral and acid detergent fiber and digestible energy intakes. A significant difference (P<.05) was observed for ether extract, being the higher value for SG66 (.83kg/day), the intermediary for SG33 (.63 kg/day) and the lower for SG0 (.50 kg/day). The slaughter weight, average daily weight gain, final body condition, feed and energetic conversions weren t influenced (P>.05) by treatments. Steers fed with SG66 stayed more time ruminating (P<.05) in relation to SG33 and SG0 animals, being values of 9.45; 8.76 and 8.61 h, respectively for SG66; SG33 and SG0. Animals fed with SG0 presented better (P<.05) dry matter and detergent fiber rumination. The time spending with feeding was higher (P<.05) for SG0 (32.58 min), intermediary for SG33 (28.33 min) and lower for SG66 (23.46 min). / O objetivo do presente estudo foi avaliar a substituição da silagem de milho por silagem de girassol na dieta, através do desempenho e do comportamento ingestivo de novilhos confinados. Foram utilizados nove novilhos castrados, com peso vivo e idade média inicial de 288 kg e 20 meses, respectivamente, pertencentes aos grupos genéticos Nelore, 21/32Charolês (C) 11/32Nelore (N) e 21/32N 11/32C. As dietas testadas foram: SG0= volumoso com 100% de silagem de milho e 0% de silagem de girassol; SG33= volumoso com 67% de silagem de milho e 33% de silagem de girassol e SG66= volumoso com 34% de silagem de milho e 66% de silagem de girassol. A relação volumoso:concentrado utilizada foi 60:40 para todas as dietas. A substituição da silagem de milho por girassol não influenciou (P>0,05) o consumo de matéria seca, de fibra detergente neutro e ácido, de energia digestível. Houve diferença (P<0,05) no consumo de extrato etéreo, sendo maior para SG66 (0,83 kg/dia), intermediário para SG33 (0,63 kg/dia) e menor para SG0 (0,50 kg/dia). O peso de abate, o ganho de peso médio diário, o estado corporal final, a conversão alimentar e energética não foram influenciados (P>0,05) pelos tratamentos. Os novilhos alimentados com SG66 ruminaram por mais (P<0,05) tempo em relação aos animais que receberam SG33 e SG0, sendo os valores de 9,45; 8,76 e 8,61 h, respectivamente, para SG66; SG33 e SG0. Animais alimentados com SG0 apresentaram melhor (P<0,05) de ruminação da matéria seca e da fibra em detergente. O tempo de despendido por refeição foi maior (P<0,05) para SG0 (32,58 min), intermediário para o SG33 (28, 33 min) e menor para SG66 (23,46 min).