No description available.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 60-62).

The study compares the biological performance of progenies of the Afrikaner x Western Sanga crossbred (small frame) and the Bonsmara (medium frame) cattle on the following traits: calving and growth rates as well as mortalities. The study was conducted in the Sourish Mixed Bushveld of the North West province. The objective was to identify a lowcare cattle breed, which can withstand unfavourable conditions under which most farmers in the North West Province operate. The results of this study indicated that, under good management, the Bonsmara cattle have higher growth rates compared to the Sanga cattle. There were statistical differences with regards to birth, pre-wean and wean masses, (P< 0.0001). Sanga cattle however were able to maintain higher calving rates under all varying conditions (Bonsmara 77% average and Sanga 84% average). The Sanga, due to its lower nutritional requirements, on average requires 15% less of the surface area required by the Bonsmara. Sanga cattle also returned better yields in terms of kilogram weaned calf per LSU and per hectare. With regard to herd mortalities, there was no significant difference (P = 0.03329).

Thesis (M. Tech.) - Central University of Technology, Free State, 2010

The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.

Made available in DSpace on 2014-06-11T19:32:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-19Bitstream added on 2014-06-13T20:24:30Z : No. of bitstreams: 1 vieirajunior_lc_dr_botfmvz.pdf: 285770 bytes, checksum: ea4f695dd363af526d84a17d75b2cab3 (MD5) / Avaliou-se o potencial e viabilidade metodológica da análise de isótopos estáveis de 13C/12C, 15N/14N e 18O/16O no sangue e plasma de bovinos de corte criados em diferentes sistemas de produção no Brasil. Os tratamentos consistiram em três sistemas de alimentação de bovinos de corte, sendo: em pasto (PA), em sistema de confinamento de animais recriados (CAR) e confinamento de animais desmamados (CAD). Foram utilizados para análise do plasma 16 bovinos, sendo 6 do PA, 4 do CAR e 6 do CAD. Já para análise do sangue foram utilizados 14 bovinos, sendo 4 do PA, 5 do CAR e 5 do CAD. Para o sangue e também para o plasma, houve distinção para todos sistemas avaliados assumindo maior representatividade na separação o elemento Carbono. Para análise da diferenciação entre os sistemas avaliados, é fundamental a participação dos 3 elementos: Carbono, Nitrogênio e Oxigênio. Para análise isotópica visando a caracterização dos sistemas de produção, recomenda-se o sangue como tecido a ser utilizado. / It was evaluated the potential application of stable isotopes methodology of 13C/12C, 15N/14N e 18O/16O in blood and plasma of beef cattle raised under three different production systems in Brazil. Treatments consisted of production systems: pasture (PA), yearling feedlot (CAR), and fed calves feedlot (CAD). For plasma, it was utilized a total of 16 samples (6 of PA, 4 of CAR and 6 of CAD). In addition, for blood it was used 14 samples (4 of PA, 5 of CAR and 5 of CAD). In both types of tissue it was possible to observe production systems differentiation, assuming greater representatively separation of Carbon element. For differentiation of production systems it is highly recommended the inclusion of Carbon, Nitrogen and Oxygen in the analysis. Based on the results, it is recommended to analyze blood for production systems differentiation by stable isotope technique

Orientador: Mário de Beni Arrigoni / Coorientador: Cyntia Ludovico Martins / Banca: Carlos Ducatti / Banca: Paulo Roberto Meirelles / Banca: Rodrigo Dias Lauritano Pacheco / Banca: Danilo Domingues Millen / Resumo: Avaliou-se o potencial e viabilidade metodológica da análise de isótopos estáveis de 13C/12C, 15N/14N e 18O/16O no sangue e plasma de bovinos de corte criados em diferentes sistemas de produção no Brasil. Os tratamentos consistiram em três sistemas de alimentação de bovinos de corte, sendo: em pasto (PA), em sistema de confinamento de animais recriados (CAR) e confinamento de animais desmamados (CAD). Foram utilizados para análise do plasma 16 bovinos, sendo 6 do PA, 4 do CAR e 6 do CAD. Já para análise do sangue foram utilizados 14 bovinos, sendo 4 do PA, 5 do CAR e 5 do CAD. Para o sangue e também para o plasma, houve distinção para todos sistemas avaliados assumindo maior representatividade na separação o elemento Carbono. Para análise da diferenciação entre os sistemas avaliados, é fundamental a participação dos 3 elementos: Carbono, Nitrogênio e Oxigênio. Para análise isotópica visando a caracterização dos sistemas de produção, recomenda-se o sangue como tecido a ser utilizado. / Abstract: It was evaluated the potential application of stable isotopes methodology of 13C/12C, 15N/14N e 18O/16O in blood and plasma of beef cattle raised under three different production systems in Brazil. Treatments consisted of production systems: pasture (PA), yearling feedlot (CAR), and fed calves feedlot (CAD). For plasma, it was utilized a total of 16 samples (6 of PA, 4 of CAR and 6 of CAD). In addition, for blood it was used 14 samples (4 of PA, 5 of CAR and 5 of CAD). In both types of tissue it was possible to observe production systems differentiation, assuming greater representatively separation of Carbon element. For differentiation of production systems it is highly recommended the inclusion of Carbon, Nitrogen and Oxygen in the analysis. Based on the results, it is recommended to analyze blood for production systems differentiation by stable isotope technique / Doutor

Thesis (MSc. (Animal breeding and genetics )) --University of Limpopo, 2006 / The objective of this study was to estimate genetic parameters for weekly body weight of feed intake of individually fed beef bulls at centralized testing stations in South Africa using random regression models (RRM). The model for cumulative feed intake included the fixed linear regression on third order orthogonal Legendre polynomials of the actual days on test (7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77 and 84 day) for starting age group and contemporary group effects. Random regressions on third order orthogonal Legendre polynomials were included for the additive genetic effect of the animal and the additional random effect of weaning-herd-year (WHY) and on fourth order for the additional random permanent environmental effect of the animal. The model for body weights included the fixed linear regression on fourth order orthogonal Legendre polynomials of the actual days on test for starting age group and contemporary group effects. Random regressions on fourth order orthogonal Legendre polynomials were included for additive genetic effects and additional uncorrelated random effects of the WHY and the permanent environment. The residual effects for both traits were assumed to be independently distributed with heterogeneous variance for each measurement period. Variance ratios for additive genetic, permanent environment and WHY for cumulative feed intake at different days on test ranged from 0.07 to 0.10, 0.53 to 0.77 and 0.14 to 0.37, respectively. Variance ratios for additive genetic, permanent environment and WHY for weekly body weights at different test days ranged from 0.26 to 0.29, 0.37 to 0.43 and 0.26 to 0.34, respectively. Estimates of genetic correlation among the same trait (body weight or feed intake) measured at different test days were generally high (>0.80) for any give test pair. The WHY had a significant contribution in variation of performance of bulls on test, despite the 28-day adjustment period. RRM provided the opportunity to study changes in genetic variability within the studied traits over time. Random Regression Models could be used in the National Genetic Evaluation of beef bulls at central performance testing stations in South Africa.

Feedlot performance, carcass merit and chemical composition were compared using Waguli , Brangus, Hereford x Tuli and Wagyu x Crossbred Gene Combination (CGC) breeds. Steers were penned in the following manner: 6 Waguli steers, 6 Hereford x Tuli, 6 Wagyu x CGC and 8 Brangus. There was a significant difference (P<0.05) between Brangus and Waguli for ADGs. F:G was lower (P<0.05) for Hereford x Tuli compared to the other crossbreeds. A heavier final weight was observed (P<0.05) for the Wagyu x CGC than all other crossbreds. There was a significant difference (P<0.05) for REA between Wagyu x CGC and Hereford x Tuli and Waguli. Wagyu x CGC had higher shear force values (SFV) (P<0.05) than all other crossbreeds. Cost of gain was lower (P<0.05) for Hereford x Tuli compared the other breeds. Hereford x Tuli also had less protein (P<0.05) than to the other breeds.A second study was conducted comparing limit feeding (LF) vs. full feeding (FF) strategies. 23 steers and 27 heifers were penned by sex and were randomly assigned a treatment; 4 pens received the LF treatment and 4 were FF. ADG was lower (P<0.05) for LF and FF heifers compared to both LF and FF steers. Dressing percentage was lower (P<0.05) for LF steers compared to LF and FF Heifers. LF heifers YG was higher (P<0.05) compared to FF steers. Quality grades were higher (P<0.05) for LF and FF heifers compared to LF and FF steers. REA /cwt was significantly higher (P<0.05) for FF heifers compared to LF and FF steers. SFV were11lower (P<0.05) for FF heifers compared to LF and FF steers. A significant difference (P<0.05) in cost of gain was noted between LF steers and the rest, also between LF heifers and FF steers. Primal cut price/cwt was significantly lower (P<0.05) for LF heifers compared to FF steers. Lipid percentage was higher (P<0.05) LF heifers compared to FF steers. Moisture percentage was lower (P<0.05) for LF heifer compared to the other groups.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The aim of this study was to provide scientifically founded guidelines to enhance the understanding of beef production from natural pastures in arid sweet veld regions. Cattle from four breed types ranging from large to small frame sizes (Simmentaler cross > Bonsmara cross > Afrikaner > Nguni) were compared in terms of cow production and efficiency as well as the growth performance, carcass and meat quality of steers slaughtered at 18, 24 and 30 months of age. Eighteen and 30 month old steers were slaughtered at the end of the wet summer season, while the 24 month old steers were slaughtered at the end of the dry winter season. The Afrikaner herd (59.8 ± 9.0 %) had lower (p < 0.05) pregnancy rates than the Simmentaler cross (79.3 ± 12.2 %), Bonsmara cross (76.5 ± 11.1 %) and Nguni herds (86.1 ± 5.8 %). Breed differences (p < 0.05) for weaning weight and preweaning gain were observed (Simmentaler cross > Bonsmara cross > Afrikaner > Nguni). The Nguni cow herd (46.5 ± 5.7 kg/100 kg mated) was more (p < 0.05) efficient than the Simmentaler cross (36.2 ± 5.5 kg/100 kg mated), Bonsmara cross (37.7 kg/100 kg mated) and Afrikaner herds (29.5 ± 5.9 kg/100 kg mated). During the dry winter season steers gained 23.4 ± 1.5 kg from 7 to 12 months of age and from 18 to 24 months of age they gained 20.9 ± 2.0 kg. During the wet summer season steers gained 109.7 ± 1.8 kg from 12 to 18 months and 120.3 ± 4.1 kg from 24 to 30 months of age. The best (p > 0.05) fat classification codes were attained at 30 months of age and the worst (p < 0.05) at 24 months of age. Simmentaler cross steers attained the lowest (p < 0.05) fat classification at all three age classes. At 30 months of age, 15 of the 63 steers slaughtered had 3 or 4 permanent incisors, while 47 steers had 2 permanent incisors. The total amount as well as the percentage kidney and omental fat were the highest (p < 0.05) at 30 months of age and the lowest (p < 0.05) at 24 months. Back fat thickness followed the same pattern. Although breed differences for some meat quality parameters were observed, slaughter age had a much more pronounced effect on meat quality parameters. The percentage cooking loss was the lowest (p < 0.05) at 30 months of age. The meat was also darker (p > 0.05) and more red (p < 0.05) at 30 months than at 18 or 24 months of age. The pH24 was higher (p < 0.05) at 24 (5.68 ± 0.05) and 30 months (5.65 ± 0.03) than at 18 months of age (5.48 ± 0.04). A trained sensory panel only detected that Longissimus muscle samples from 18 month old steers were more tender (p < 0.05) than that from 30 month old steers. Similar results were found for Warner-Bratzler shear force values. Marketing steers at 30 months of age resulted in higher production outputs for all the breed types than marketing weaners. For marketing both weaners and 30 month old steers the Nguni herd produced more marketable kilograms live weight than the Simmentaler cross, the Bonsmara cross and the Afrikaner herds. Different marketing systems suitable to the Arid Sweet Bushveld were identified. Each marketing system is discussed in terms of its application, advantages, disadvantages and adaptability to arid regions. It is maintained throughout that a conservative approach to grazing as well as cattle management is critical to ensure stable production systems in arid regions with erratic rainfall patterns. / AFRIKAANSE OPSOMMING: Die oogmerk van hierdie studie is om wetenskaplik gefundeerde riglyne daar te stel wat die begrip van beesvleis produksie vanaf natuurlike weidings in ariede soetveld streke sal verbeter. Beeste van vier ras tipes wat wissel van groot- tot kleinraam tipes (Simmentaler kruis > Bonsmara kruis > Afrikaner > Nguni) is vergelyk in terme van koeiproduksie en effektiwiteit sowel as die groei prestasie, karkas- en vleiskwaliteit van osse op 18-, 24- en 30-maande ouderdom. Osse wat op 18 en 30 maande ouderdom geslag is, is aan die einde van die nat somerseisoen geslag, terwyl osse wat op 24 maande ouderdom geslag is, aan die einde van die droë winterseisoen geslag is. Die Afrikaner kudde (59.8 ± 9.0 %) het ’n laer (p < 0.05) reproduksietempo as die Simmentaler kruis (79.3 ± 12.2 %), Bonsmara kruis (76.5 ± 11.1 %) en die Nguni kuddes (86.1 ± 5.8 %) gehandhaaf. Ras verskille (p < 0.05) ten opsigte van speenmassas en voorspeense groeitempo’s is waargeneem (Simmentaler kruise > Bonsmara kruise > Afrikaners > Ngunis). Die Nguni koei kudde (46.5 ± 5.7 kg/100 kg gedek) was meer (p < 0.05) effektief as die Simmentalerkruis (36.2 ± 5.5 kg/100 kg gedek), Bonsmarakruis (37.7 kg/100 kg gedek) en die Afrikaner kuddes (29.5 ± 5.9 kg/100 kg gedek). Gedurende die droëwinter seisoen het die osse vanaf 7 to 12 maande ouderdom 23.4 ± 1.5 kg in liggaamsmassa toegeneem en vanaf 18 tot 24 maande ouderdom het hulle 20.9 ± 2.0 kg toegeneem. Gedurende die nat somerseisoen het die osse vanaf 12 tot 18 maande ouderdom 109.7 ± 1.8 kg in liggaamsmassa toegeneem en van 24 tot 30 maande ouderdom het hulle 120.3 ± 4.1 kg toegeneem. Die beste (p < 0.05) vetklassifikasie kodes is op 30 maande ouderdom verkry en die swakste (p < 0.05) op 24 maande ouderdom. Simmentalerkruisosse het by alle ouderdomsgroepe die swakste (P < 0.05) vetklassifikasie kodes behaal. Op 30 maande ouderdom het 15 van die 63 osse wat geslag is 3 of 4 permanente snytande gehad, terwyl 47 osse 2 permanente snytande gehad het. Die totale hoeveelheid sowel as die persentasie nier- en omentumvet was die hoogste (p < 0.05) op 30 maande ouderdom en die laagste (p < 0.05) op 24 maande ouderdom. Rugvetdikte het dieselfde patroon gevolg. Alhoewel rasverskille vir sommige vleiskwaliteitsparameters waargeneem is, het slagouderdom’n groter effek hierop. Die persentasie kookverlies was die laagste (p < 0.05) op 30 maande ouderdom. Die vleis was ook donkerder (p < 0.05) en meer rooi (p < 0.05) op 30 maande ouderdom as op 18 en 24 maande ouderdom. Die pH24 was hoër (p < 0.05) op 24 (5.68 ± 0.05) en 30 maande ouderdom (5.65 ± 0.03) as op 18 maande ouderdom (5.48 ± 0.04). Behalwe vir sagtheid, is geen ander ras- of slagouderdomsverskille in die longissimus spiermonsters vir enige van die sensoriese eienskappe wat geëvalueer is, waargeneem nie. ’n Opgeleide sensoriese paneel het slegs waargeneem dat die longissimus spiermonsters van 18 maand oue osse sagter (p < 0.05) was as dié van 30 maand oue osse. Soortgelyke resulte is vir die Warner-Bratzler snyweerstand gevind. Die bemarking van 30 maand oud osse het hoër produksie uitsette vir al die ras tipes opgelewer as die bemarking van speenkalwers. Met die bemarking van beide speenkalf en 30 maand oue osse, het die Ngunikudde meer bemarkbare kilogram lewendige massa as die Simmentalerkruis, die Bonsmarakruis en die Afrikaner kuddes geproduseer. Verskillende bemarkingstelsels wat as geskik vir die Ariede Soet Bosveld beskou word, is geïdentifiseer. Elke bemarking stelsel is in terme van sy toepassing, voor- en nadele asook die toepaslikheid daarvan in ariede streke bespreek. Dit word deurgaans aanbeveel dat ’n konserwatiewe benadering tot beide weidings- en kuddebestuur, krities is om stabiele produksiestelsels in ariede streke met wisselvalige reënvalpatrone te verseker.