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This study investigated the hypothesis that cattle fed to produce a lean carcass during a winter restriction period will subsequently grow faster and remain leaner than fatter steers during the summer, exploiting cheap grazed grass. Three studies were carried out; in the first study steers were restricted at three levels of growth (300, 600 and 900 g/day) during winter and turned out to graze grass during summer. At each level of growth during winter steers were fed on one of two diets aimed at producing steers of either a lean or fat carcass composition. At the end of the winter restriction period differences in lean composition were observed at the 300 and 600 g/day growth rates. Steers were slaughtered when they attained the target slaughter weight at the end of summer; but there was no difference between treatments in meat quality characteristics or fat composition. Liveweight gain during the summer period was inversely correlated to winter liveweight gain. Two further studies were carried out to assess the effect of altering carcass composition during winter, fed to a predicted growth rate of 600g/day to investigate the underlying physiological and endocrinological mechanism regulating the growth characteristics. In the first study at the end of winter steers that were fatter had higher glucose and insulin concentrations. No differences between diet treatments were detected in muscle protein synthesis or breakdown. At the end of the winter in the second experiment there were no differences in carcass composition, metabolite or hormone profiles between treatments. For both studies, at the end of summer, steers on different dietary treatments had similar carcass compositions and metabolic parameters. It was concluded that by altering the diet of steers during a winter restriction period the composition of carcass gain can be manipulated. Since steers altered the deposition of carcass protein and fat during the subsequent summer period at grass resulting in similar body compositions at slaughter it was deduced the that composition of steers at the end of winter remains unimportant. Reductions in beef production costs may be attained by restricting the growth rates during winter when commercial feeds are expensive.

LD2668 .T4 1947 M4 / Master of Science

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An industrial Fourier transform infrared (FTIR) milk analyser has been adapted for the proximate analysis of fresh or cooked meat and meat products. Stable freeze-dried samples of ground beef and bologna were prepared for the calibration of an FTIR spectrometer equipped with a 37-mum transmission cell maintained at a constant temperature of 65°C and were analysed for fat, protein, moisture, and ash by the official methods of analysis of the Association of Official Analytical Chemists (AOAC) prior to instrumental measurement. The requirement to prepare a "milk-like" emulsion of meat for FTIR analysis led to the development of two prototype high-pressure homogenizers specifically designed to produce analytical volumes of emulsions in which the largest residual colloids present in suspension would have dimensions smaller than 1 mum. Emulsified samples were examined by transmission electron microscopy and laser light scattering spectroscopy to determine the size distribution of fat globules and the dimensions of the residual insoluble fragments of protein. / "Milk-like" emulsions of meat passed three times through a high-pressure homogenizer operating at 20,000 psi (138 MPa) had an average fat globule diameter of less than 320 nm. Also, the use of high-pressure homogenization eliminated the need to filter out insoluble proteins from connective tissues prior to the infrared analysis, resulting in a more accurate determination of the protein content in the meat samples. The results of validation studies conducted with both fresh and freeze-dried samples demonstrated that it is possible to analyse meat samples simultaneously for fat, protein, carbohydrates and moisture with good accuracy in approximately 7½; minutes per sample employing existing FTIR instrumentation used for the routine analysis of milk and dairy products.

Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Production Physiology))--University of Pretoria, 2000. / Animal and Wildlife Sciences / unrestricted

Made available in DSpace on 2014-06-11T19:33:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-28Bitstream added on 2014-06-13T19:04:38Z : No. of bitstreams: 1 boiago_mm_dr_jabo.pdf: 456558 bytes, checksum: 5fedc7f36c4c91c58db0f60b0bc4ccb5 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Avaliou-se o desempenho, qualidade e composição química da carne, resistência óssea e empenamento de frangos de corte arraçoados com dietas contendo selênio, zinco e manganês complexados ou não a moléculas orgânicas e criados sob condições de estresse térmico. Foram utilizados 980 pintos machos Cobb de um dia de idade, criados até 42 dias de idade em três câmaras climáticas, que proporcionaram temperaturas alta, termoneutra e baixa. Foi utilizado o delineamento inteiramente casualizado, em esquema fatorial 3 X 2 + 1, sendo três temperaturas de criação, duas fontes de selênio, zinco e manganês: inorgânica e “orgânica”, mais o tratamento testemunha (criação em câmara termoneutra sem adição de Se, Zn e Mn na ração). As aves criadas em condições de estresse térmico apresentam desempenho inferior e ossos com densidade óssea e resistência à quebra menores. A fonte orgânica proporcionou melhor desempenho, principalmente em condições de temperaturas elevadas. Selênio e zinco foram melhor absorvidos na forma orgânica, já o manganês teve absorção similar nas duas formas. As aves criadas em temperaturas baixas apresentaram carne menos macia. O empenamento das aves não foi influenciado pelos fatores testados / It were evaluated performance, meat quality and composition, bone strength and feathering of broilers fed supplemented diets with different selenium, zinc and manganese sources (organic and inorganic) and raised under different environmental temperatures. Nine hundred and eighty one d. old Cobb male broilers were used during 42 days. It were used three climatic chambers (high, neutral and low temperatures) and twenty chickens per pen. It was used a 3x2 + 1 factorial arrangement (three breeding temperatures, two mineral sources and a control treatment that provided neutral temperature without mineral supplementation) with seven replicates. The means were compared by Tykey's test (5%).The thermal stressed broilers showed lower performance, bone density and strength. The organic source took to a better performance, mainly under high temperatures. Organic sources of selenium, zinc and manganese were highly absorbed, however, the absorption of both sources of manganese was similar. Chickens raised under low temperatures presented lower values of tenderness. The factors didn't influence the feathering of the chickens

Submitted by Katiane Souza (katyane.souza@gmail.com) on 2016-03-19T19:32:08Z No. of bitstreams: 1 arquivototal.pdf: 1177944 bytes, checksum: 25733b13d84378d80aa1d4f47a73a7a5 (MD5) / Made available in DSpace on 2016-03-19T19:32:08Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1177944 bytes, checksum: 25733b13d84378d80aa1d4f47a73a7a5 (MD5) Previous issue date: 2010-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Two experiments were conducted in order to assess the nutritional value of hay maniçoba (FM) compared with alfalfa hay (FA) as an ingredient in the diet of growing rabbits-finish. In experiment 1 were determined digestibilities of dry matter (DMD), crude protein (CPD), ether extract (DEE) and digestible energy (DE) was analyzed. 14 rabbits were used in growth, delivered in a completely randomized design with seven replications. FM presented at natural matter, 67.40% of DMS, 35.05% of BDP, 11.87% of DEE and 709 kcal DE / kg. In experiment 2, we used 56 rabbits (28 castrated males and 28 females) to evaluate the growth performance parameters, and carcass and meat composition. We evaluated increasing levels of replacement of the FA PB by PB FM at 0, 25, 50 and 75%. The experimental design was a completely randomized design with four treatments and seven replications, and housed two animals per experimental unit. The data were analyzed using the SAS program. Feed intake increased linearly as weight gain, feed conversion, live weight, hot carcass weights and cold and weight of the skin had a quadratic effect with maximum levels of substitution of crude protein (CP) of the FA protein of FM of respectively 58, 34.9, 54, 50, 50 and 50% respectively. The results of carcass composition showed that the percentage of CP increased to 31.6%, the ability to retain water up to 36.7%, while the fat percentage peaked in the substrate with 46.5% replacement of CP FA by PB FM. There was no effect of treatments on the levels of oleic fatty acids, lauric and palmitic acids in the muscle biceps femoris. Hay maniçoba contains 14.89% protein, 67.4% of DMS and 709 kcal DE / kg in MN. It is recommended to replace 58% of the FA PB by PB FM, with the additions of 14.33 kg of FM and 8.78 kg of FA/100 kg. / Foram conduzidos dois experimentos, com o objetivo de avaliar o feno de maniçoba (FM) em comparação com o feno da alfafa (FA) como volumoso na ração de coelhos em crescimento-acabamento. No experimento 1 foram determinadas as digestibilidades da matéria seca (DMS), proteína bruta (DPB), extrato etéreo (DEE) e a energia digestível (ED) das rações. Foram utilizados 14 coelhos em crescimento, distribuídos num delineamento inteiramente casualizado com sete repetições. O FM apresentou, na matéria natural, 67,40% de DMS, 35,05% de DPB, 11,87% de DEE e 709 kcal de ED/kg. No experimento 2 foram utilizados 56 coelhos (28 machos castrados e 28 fêmeas) para a avaliação do desempenho zootécnico, peso e rendimento de carcaça e composição da carne. Foram avaliados níveis crescentes de substituição da PB do FA pela PB do FM em 0; 25; 50 e 75%. O delineamento utilizado foi o inteiramente casualizado com quatro tratamentos e sete repetições, sendo alojados dois animais por unidade experimental. Os dados foram analisados através do programa SAS. O consumo de ração aumentou linearmente, enquanto o ganho de peso, conversão alimentar; peso vivo, pesos da carcaça quente e fria e peso da pele apresentaram efeitos quadráticos com níveis máximos de substituição da proteína bruta (PB) do FA pela proteína bruta do FM de, respectivamente, 58; 34,9; 54; 50; 50 e 50%, respectivamente. Os resultados da composição da carcaça mostraram que o percentual de PB aumentou até 31,6% e a capacidade de retenção de água até 36,7%, enquanto, o percentual de gordura máximo na carcaça foi com 46,5% de substituição da PB do FA pela PB do FM. Não houve efeito dos tratamentos sobre os níveis dos ácidos graxos oléico, láurico e palmítico no músculo Bíceps femoris. O feno de maniçoba contém 14,89% de proteína, 67,4% de DMS e 709 kcal de ED/kg na MN. Recomenda-se substituir 58% da PB do FA pela PB do FM, com as inclusões de 14,33 kg de FM e 8,78 kg de FA/100 kg de ração.

Thesis (MScVoedselwet)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Two experiments were conducted in order to manipulate the physical and chemical properties and shelf life of ostrich meat. Experiment 1: The effect of dietary fish oil rich in n-3 fatty acids on the organoleptic, fatty acid and physicochemical characteristics of ostrich meat. The diet of four ostrich groups (15 birds per group), approximately 3 months of age (ca. 41 kg live weight) grazing a predominantly oats pasture, was supplemented with a diet containing 6.7% fish oil. The birds received a supplement of either 0 (diet 1), 800 (diet 2), 1600 (diet 3) or 2400 g (diet 4) DM/day resulting in the consumption of 0 (diet 1), 14.5 (diet 2), 29 (diet 3) and 43.5 (diet 4) g fish oil per day. The ostriches were slaughtered at 10 months of age (ca. 70 kg live weight). An increase in the amount of fish oil consumed was found to have had statistically no significant effect on the sensory characteristics of the M. iliofibularis, although there was a tendency towards an increase in ‘fishiness’, for both aroma and flavour. However, increased concentrations of fish oil had a significant effect on the aroma and flavour of the abdominal fat pads. The muscle pHf and muscle lightness (L*) reflected a significant reduction with increased fish oil levels. The increased feed intake, on the other hand, had no effect on the chemical composition (moisture, protein, fat and ash content) of the meat. The fatty acid profile of both fat and meat was affected by the consumption of fish oil. The SFA concentration increased, while the PUFA concentration decreased, with an increase in feed intake. The MUFA concentration remained constant for all four groups. Experiment 2: The effect of dietary vitamin E and the type of packaging on the sensory quality, physicochemical composition and shelf life of ostrich meat. Two groups of ostriches (35 birds per group; ca. 3 months old) were fed diets containing either 40 mg/kg feed vitamin E (control) or 150 mg/kg feed Vitamin E for nine months. The birds were slaughtered at 12 months of age. The effect of different the levels of vitamin E and heat shrink treatment of vacuum packaging material on the shelf life of refrigerated (0°C) ostrich M. flexor cruris lateralis, was evaluated over 81 days. Vitamin E and heat shrink treatments were found to have had no significant effect on the sensory characteristics; off-meat aroma, sourness, juiciness and mealiness. Rancidity was found to be slightly more pronounced (although not statistical significant) in the vitamin E and heat shrink groups than in the feed control and vacuum-packed groups. A significant decrease in the organoleptic quality of the meat, over a 40 day shelf life period, was observed. The pH and muscle tenderness showed a significant reduction with increased storage time. The purge loss in the package increased over time with no change in muscle drip loss. The colour, conjugated dienoic acid and fatty acid content showed no significant changes over time or with regards to treatment. The total viable counts and coliform numbers in the muscle increased over time, with the coliforms being slightly suppressed by the inclusion of vitamin E in the diet. A microbiological safe shelf life of 40 days at 0°C was obtained. / AFRIKAANSE OPSOMMING: Twee eksperimente is uitgevoer om die fisiese en chemiese eienskappe, asook die rakleeftyd van volstruisvleis, te manipuleer. Eksperiment 1: Die effek van visolie, ryk aan n-3 vetsure, op die organoleptiese, vetsuur- en fisies-chemiese eienskappe van volstruisvleis. Die dieet van vier groepe volstruise (15 voëls per groep), ongeveer 3 maande oud (ca. 41 kg lewende massa) wat ‘n hawer weiding bewei het, is aangevul met ‘n byvoedingsmengsel wat 6.7% visolie bevat en in toenemende hoeveelhede vir die groepe volstruise gevoer is. Die voëls het ‘n aanvulling van 0 (dieet 1), 800 (dieet 2), 1600 (dieet 3) of 2400 g (dieet 4) DM/dag ontvang wat gelei het tot ‘n inname van 0 (dieet 1), 14.5 (dieet 2), 29 (dieet 3) en 43.5 (dieet 4) g visolie per dag. Die volstruise is op ‘n ouderdom van 10 maande geslag (ca. 70 kg lewende massa). ‘n Toename in die hoeveelheid visolie ingeneem, het geen statisties betekenisvolle effek op die sensoriese eienskappe van die M. ilifibularis gehad nie, alhoewel daar ‘n tendens was vir ‘n toename tot ‘n ‘visagtige’ aroma en smaak. ‘n Toename in die konsentrasie visolie het egter ‘n betekenisvolle effek op die ‘visagtige’ aroma en smaak van die abdominale vet neerslae gehad. Die spier pHf en spier ligtheid (L*) het ‘n betekenisvolle afname met toename in voer inname getoon. Die verhoogde olie inname het egter geen effek op die chemiese samestelling (vog-, proteïen-, vet- en asinhoud) van die vleis gehad nie. Die vetsuurprofiel van beide die abdominale vet neerslae en die vleis is deur die inname van visolie verander. Die versadigde vetsuurkonsentrasie het verhoog terwyl die poli-onversadigde vetsuurkonsentrasie verlaag het met ‘n toename in rantsoenvlakke. Die mono-onversadigde vetsuurkonsentrasie het egter konstant gebly vir al vier groepe. Eksperiment 2: Die effek van vitamien E en die tipe verpakking op die sensoriese kwaliteit, fisies-chemiese samestelling en rakleeftyd van volstruisvleis. Twee groepe volstruise (35 voëls per groep, ongeveer 3 maande oud) het voere oor ‘n tydperk van nege maande ontvang wat 40 mg vitamien E/kg voer (kontrole) of 150 mg vitamien E/kg voer bevat het. Die voëls is op 12 maande ouderdom geslag. Die effek van die verskillende vlakke van vitamien E en hitte-behandeling van die verpakkings materiaal op die rakleeftyd van verkoelde (0°C) volstruis M. flexor cruris lateralis, is oor 81 dae geëvalueer. Vitamien E en die hitte-behandeling het geen betekenisvolle effek op die organoleptiese eienskappe (af-vleis aroma, suurheid, sappigheid en melerigheid) gehad nie. Galsterigheid was ‘n bietjie meer gedefinieerd (anie-betekenisvol) in die vitamien E en hitte behandelde groepe as in die rantsoen kontrole en vakuum verpakte vleis. ‘n Betekenisvolle afname is waargeneem in die organoleptiese kwaliteit van die vleis oor ‘n 40 dae rakleeftyd periode. Die pH en taaiheid van die spier het betekenisvol afgeneem met ‘n toename in bergingsperiode. Die drup verlies tydens verpakking het ook oor tyd toegeneem, terwyl geen verandering in die analitiese drup verlies van die spier verkry is nie. Die kleur, gekonjugeerde dieensuur en vetsuursamestelling het geen verandering oor tyd of ten opsigte van behandeling getoon nie. Die Totale Lewendig Seltelling en coliforme het toegeneem oor tyd, terwyl die coliforme deur die byvoeging van vitamien E tot ‘n mate onderdruk is. ‘n Mikrobiologies veilige rakleeftyd van 40 dae is verkry.