• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • Tagged with
  • 4
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of pre-slaughter stress of pigs on the levels of cortisol, creatine kinase and their subsequent relationship with pork quality

Nzolo, Jama January 2014 (has links)
The study was conducted to determine the effect of pre-slaughter stress of pigs on the levels of cortisol, creatine kinase (CK) and their subsequent relationship with pork quality. From our knowledge, there is paucity of information on transportation, lairage duration and sex effects on saliva cortisol and its relation with serum cortisol, urine cortisol and other meat quality traits. Stage one of the study assessed the effect of sex and time to slaughter (transport and lairage duration) on the levels of cortisol and CK in crossbred pigs. The second stage of the study evaluated the effect of sex and lairage duration on pork quality. The trials comprised of 60 22-weeks old commercial crossbred pigs [(30 boars vs. 30 gilts) with an average body weight of 76.9kg for gilts and 78.3kg for boars. Thirty pigs (15 Boars vs. 15 Gilts) were slaughtered on arrival after a 120km road journey and the other 30, after travelling the same road and distance, were slaughtered after having been in the lairage for 20 hours. Saliva samples were obtained during three time periods: between 07:00-10:00 on the day before the journey, on arrival at the abattoir and after lairage. Levels of cortisol in serum and urine and CK in serum samples collected at slaughter were determined. The samples (saliva and serum) were centrifuged at 20oC for 10 min at 3550 x g and stored at -20oC in separate vials until analysis. Pork quality was assessed using muscle pH, colour, thawing and cooking losses and Warner-Bratzler Shear Force. Correlations between cortisol levels in saliva, serum and urine and meat quality were assessed. The effect of sex and time to slaughter on saliva cortisol was significant. Statistical analysis showed significant interaction of sex by time to slaughter on serum cortisol. It was only the effect of sex that demonstrated higher (P <0.05) serum creatine kinase levels in gilts. Likewise, urine cortisol was influenced (P <0.05) only by time to slaughter. Saliva cortisol after transportation (r = 0.52) was correlated (P <0.05) with urine cortisol. The study suggests that there are greater responses of the Hypothalamic-pituitary-adrenal axis following time to slaughter (transport and lairage duration) between gilts and boars. This can be used in measuring cortisol in saliva, serum and urine, and serum creatine kinase to determine stress levels in pigs. Besides the lightness (L*) colour value which was significantly lower (P <0.05) in meat from gilts than from boars, the results of this study showed no interaction or individual effect (sex or lairage duration) on pH and other colour measurements. Meat cooking loss was affected (P <0.05) by gender x lairage interaction. Effect of lairage duration (as an individual effect) on the measured meat quality traits was not significant (P <0.05). Correlation analysis showed significant (P <0.05) negative relation between baseline saliva cortisol (r = -0.40) and the pork L* value. Saliva cortisol after lairage duration (r = -0.38 and r = 0.38) was correlated (P <0.05) with pH45 and pork a* value, respectively. Serum cortisol (r = -0.35) was negatively correlated (P <0.05) with pH45. Moreover, there were negative correlations (P <0.05) between saliva cortisol after transportation (r = -0.35), saliva cortisol after lairage duration (r = -0.44), serum cortisol (r = -0.40) and meat cooking loss. The study suggests that cortisol in saliva and serum can be used to determine effect of time to slaughter (transport and lairage duration) on meat quality traits from gilts and boars. Keywords: Boars; gilts; saliva cortisol; serum cortisol; serum creatine kinase; urine cortisol.
2

A psychobiographical study of Temple Grandin

Wannenburg, Nicola January 2018 (has links)
Psychobiographical researchers methodically formulate life histories and interpret them by means of psychological theories. The research typically focuses on exemplary and completed lives. The cases that are studied are usually of individuals who are of particular interest to society as a result of excelling in their particular fields, be they to benefit or detriment of society. Temple Grandin was chosen for this study using purposive sampling as she meets the psychobiographical requirement of being an extraordinary individual. As an individual with autism Grandin faced many challenges growing up. Despite a difficult and absent beginning, Grandin developed into a stable and scientifically creative adult who contributes to society. She excels as an animal scientist and designer of humane livestock handling facilities and has an international reputation for her contribution to the livestock industry and animal welfare. The primary aim of this study is to describe and interpret the life of Temple Grandin through Erikson’s (1950/1973) theory of psychosocial development. A mixed method approach (Yin, 2006) was employed for the conduction of this study. The overarching data processing and analysis guidelines for this study were provided by Miles and Huberman (1994, 2002a, 2002b). The conduction of the processing and analysis of data was aided by Alexander’s (1988, 1990) method of asking the data questions as well as an integration of Yin’s (2014) time series analysis with Erikson’s (1950/1973) triple bookkeeping approach. This study contributes to the development of psychobiographical research in South Africa as well as to personality and developmental theory.
3

Consumer perceptions and values on beef quality: implications on beef markets

Mabhera, Sunungukai. January 2015 (has links)
Beef constitutes an important part of many consumers’ diets. Beef is the most consumed red meat in South Africa. Consumer perceptions can affect the whole supply or value chain of beef. Recently there has been increased interest in food safety; greater concern for environmental and animal welfare issues, increased importance of eating quality and healthy food as well as the greater role of food services. The demand for beef is no longer limited to economic factors alone but to non-economic factors as well. Consumers of beef in Alice have become more concerned about meat-borne risks and personal health. This research prioritized the exploration of the beef consumers’ (i) self-perception (ii) price perception (iii) benefit perception [in the form of – (a) value perception and (b) quality perception]. The study was conducted in the Eastern Cape Province specifically in Alice town and the surrounding rural areas (Ntselamanzi, Gaga, Hillcrest, Gqumashe, and Dyamala) of the Nkonkobe municipality. Anyone who admitted to eating beef and at the point of data collection bought beef for their own consumption or family consumption was deemed as a unit of analysis. Non – probabilistic sampling techniques which included accidental and random sampling were used to collect data from 100 interviewees. A semi structured questionnaire was used to analyse the perceptions and attitudes of beef consumers. The respondents were asked to indicate their agreement or disagreement with 47 statements or items presented on either five alternatives in a Likert scale scored from 1 (strongly disagree) to 5 (strongly agree) or a six Likert scale ranging from 1 (very low) through 5 (very high) to 6 (I do not know).The data was analysed using SPSS. It was discovered that beef consumers did not consider either intrinsic or extrinsic cues in isolation when purchasing beef but rather all characteristics contribute to the final perception. The Alice consumer market is heterogeneous and consists of different races with different cultures and market segments with varying needs and preferences. The results showed that five factors were extracted from forty seven items Factor 1: Information reliance and quality indication; Factor 2: convenience; Factor 3: Traceability and animal Welfare; Factor 4: Health and safety Conscious and Factor 5: Price and Branding. Furthermore, four main consumer segments emerged as - Segment 1: Informed buyers; Segment 2: Elite buyers; Segment 3: Health & safety conscious buyers and Segment 4: Apathetic buyers. The cluster analysis shows that quality is a subjective concept that is informed by a consumer’s personal taste and preferences. Taste and preferences inform the consumer’s effective demand which in retrospect is informed by the consumer’s socioeconomic status.
4

The effects of distance travelled, lairage duration and animal-related factors on pre-slaughter stress indicators, carcass characteristics, nanostructure and technological properties of beef

Chulayo, Amanda Yucca January 2015 (has links)
The main objective of the current study was to determine the effect of distance travelled (DT), lairage duration (LDhr) and animal-related factors (animal class, breed, sex) on pre-slaughter stress indicators, carcass characteristics, nanostructure and technological properties of beef. The study was conducted in an Eastern Cape abattoir under the Buffalo City District Municipality. Six genotypes of cattle (Beefmaster, Bonsmara, Brahman, Holstein-Friesian, Non-descript and Nguni) brought for slaughter at the abattoir on different days were used in the study. Slaughter weight (SWT), warm and cold carcass weight (WCW and CCW), fatness and conformation of each animal were measured and recorded. Representative samples of blood plasma and meat quality from the Muscularis thoracis et lumborum (LTL) were collected at slaughter and 24 hours after slaughter, respectively. Heat shock proteins 70kDa (HSPA1A), glucose (GLU), cortisol (CORT), creatine kinase (CK) and lactate dehydrogenase (LDH) were determined from the blood plasma. The representative LTL muscle was used to determine ultimate pH (pHu), lightness (L*), redness (a*), yellowness (b*), meat temperature (Tm), Warner Bratzler Shear Force (WBSF) and histological structure of beef. There were significant effects of distance on pHu, Tm, a*, b*, TL%, CK and LDH. Pearson correlations were observed between distance travelled (DT), creatine kinase (CK), lactate dehydrogenase (LDH), ultimate pH (pHu), colour coordinates (L*, a* and b*) and Warner Bratzler Shear Force (WBSF). Principal component analysis (PCA) revealed that the 1st (pHu), 2nd (Tm) and 3rd (L*) principal components were the critical meat quality attributes. Positive relationships between carcass weights and beef quality characteristics for bovine cattle where the cumulative percentage of the first six principal component`s (PC`s) (SWT, WCW, CCW, DP, pHu and Tm contributed to 93.4 % of the total variance. Significant correlation coefficients between DT (r = 0.15), LDhr (r = 0.29), Ta (r = -0.52), Tm (r = 0.26), L* (r = 0.33), a* (r = 0.32) and WBSF (r = -0.49) were observed. Meat from Brahman (BR), Non-descript (ND) and Nguni (NG) cows had visible skeletal muscle fibres which were thin and long indicating improved tenderness of beef. Exposing animals to longer hours of transportation did not only reduce glucose levels but also increased the expression of HSPA1A and levels of cortisol. The CK and LDH were not related to beef quality. Therefore, CK and LDH can be used as indicators of animal welfare in slaughter cattle but cannot be used to predict the quality of meat. Bulls were the heaviest, although heifers had the highest dressing percentage than cows. Furthermore, the nanostructure of beef indicated that heifers had the best muscle fibres, sarcomere length and visible intercalated discs. The observed nanostructures of Nguni genotype are an indication of tender meat. Beef from heifers of Nguni had visible and tender meat with traces of intramuscular fat while males had shorter sarcomere length and tougher meat.

Page generated in 0.0514 seconds