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Effects of pre-slaughter stress, sex and breed on blood stress indicators, heat shock proteins, glycolytic potential and lamb quality

  • Authors: Stempa, Thuthuzelwa
  • Date: 2019
  • Subjects: Animal welfare , Meat--Quality
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/15376 , vital:40402
  • Description: The main objective of this study was to determine the effects of pre-slaughter stress (transportation distance and lairage duration), sex and breed on blood stress indicators, heat shock proteins, post-mortem muscle metabolites (glycogen, glucose, glucose-6-phosphate and lactate), glycolytic potential and meat quality attributes from lambs slaughtered at a commercial abattoir. The study was conducted in a high-throughput commercial abattoir in the Buffalo City local municipality of the Eastern Cape Province, South Africa. A total of a hundred eight-month old Dorper and Merino lambs, both male and female, were used in the study. Blood samples for the analysis of glucose and lactate levels were collected using 10.0 mL disposable Becton Dickinson vacutainer tubes treated with fluoride oxalate (grey top) whereas those for determination of cortisol and heat shock protein 70 (HSPA1A) levels were collected using plasma separating vacutainer tubes (SSTTMII, gold top), and those for analysis of creatine kinase and lactate dehydrogenase were collected using 10.0 ml vacutainer tubes treated with Ethylenediaminetetraacetic acid (EDTA). Meat samples (~50 g) for the measurement of post-mortem energy metabolites (glycogen, lactate glucose-6-phosphate and glucose content) were collected from the Muscularis longimissius thoracis et lumborum (LTL) of each carcass ~30 minutes after slaughter and immediately frozen in liquid nitrogen (-196 oC) to prevent further glycolysis. Cold carcass weight (CCW), warm carcass weight (WCW) and carcass fatness (CF) was measured. Meat pH and temperature were measured at iii 45 minutes (initial pH), 6 hours and 24 hours ultimate pH (pHu) post-mortem. Meat colour coordinates [lightness (L*), redness (a*), yellowness (b*), hue angle (H*), chroma (C*)] were also measured 24 hours after slaughter. Furthermore, thawing loss (TL%), cooking loss (CL%) and warner braztler shear force (WBSF) was measured in the LTL 7 days post slaughter. Breed had a significant effect on plasma HSPA1A, plasma lactate, WCW, CCW, L*, muscle glycogen and WBSF. Sex had a significant effect on plasma HSPA1A and pHu. Pearson‘s correlations showed that meat muscle glycogen was positively correlated to glycolytic potential (P<0.001; r=0.63) and initial pH (P<0.05, r=0.20). Muscle lactate was positively correlated to muscle glucose (P<0.01, r=0.30) and glycolytic potential (P<0.001, r=0.79). A positive correlation was shown between muscle glucose and glycolytic potential (P<0.05, r=0.23). The level of LDH was affected by the distance travelled by lambs prior to slaughter. Lairage duration did not affect the levels of CK and LDH. Principal Component Analysis showed a relationship between distance travelled and CK and LDH; and that CK and LDH also influenced the quality of meat from lambs. With respect to sex and breed, the results indicate that female and Dorper were more stressed than male and Merino respectively. Muscle glycolytic potential and post-mortem metabolites have an impact on the quality of meat produced and the Merino had higher muscle glycogen levels at slaughter; hence they produced better meat quality compared to the Dorper. Moreover, no associations were seen between pHu and blood stress indicators. These results indicate that blood stress indicators at exsanguination cannot be used as useful indicators of dark cutting condition in lamb. A relationship between pHu, muscle glycogen and glycolytic potential was established and thus meat pHu can be used as a reliable indicator of tenderness in lamb.
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  • Date Issued: 2019

Socio-economic importance, health and welfare aspects of donkeys (Equus asinus) used for carting in a peri-urban area of South Africa

  • Authors: Marufu, Madure
  • Date: 2014
  • Subjects: Donkeys -- South Africa , Animal welfare , Donkeys -- Handling , Donkeys -- Health
  • Language: English
  • Type: Thesis , Masters , MSc Agric (Animal Science)
  • Identifier: vital:11832 , http://hdl.handle.net/10353/d1019781 , Donkeys -- South Africa , Animal welfare , Donkeys -- Handling , Donkeys -- Health
  • Description: The broad objective of the study was to determine the socio-economic importance, health and welfare aspects of donkeys used for carting in a peri-urban area. A survey was conducted among 71 donkey owners in Joza, a peri-urban area near Grahamstown in the Eastern Cape Province (ECP) of South Africa to investigate their perceptions on socio-economic importance, health and welfare aspects of donkeys used for transport. Two hundred and seventy-one donkeys used for carting were assessed through direct observation of health and behaviour parameters to determine their welfare status. Results revealed that donkeys are indeed of immense value to people, being used daily (54.93%) for income generation activities and at least once per month (7.08%) for domestic chores. Most of the respondents (32%) earned R 600.00 per week while 11% earned at least R 200.00 per week from carting using donkeys. Donkeys were used for carting of goods (90.14%) more than for manure (16.9%). Gender and age of owners significantly (P < 0.05) influence perceptions on source of income while education level influenced their perceptions on carting firewood, goods and water. Results on management practices and health problems encountered by working donkeys showed that most of the owners managed their animals poorly. Most donkeys were being beaten (74.65%) during work, made to travel long distances (43.66%), worked long hours (52.11%) without adequate water (59.10%) and feed supplements (83.10%). Wounds (95.97%), coughing (75.65%) and lameness (64.79%) were some of the health problems encountered by donkeys. Significant relationships (P ˂ 0.05) were observed between owners’ perceptions on management practices and health problems encountered by donkeys. Among the observed animals, 61% were thin and mostly apathetic (26.2%) than medium and fat animals. Responses to observer approaches were significantly associated with sex and body condition score (BCS), with stallions in good body condition being more aggressive. Donkeys having a BCS of 3-5 avoided chin contact either by kicking out or moving away. Results further showed that most of the donkeys were suffering from external injuries, with the hindquarters (39.85%), shoulder (32.10%) and spine (21.77%) being the mostly affected areas. The prevalence of wounds on tail-base, belly, flank and neck were seen in less than 13% of the animals. The prevalence of wounds was influenced by age and BCS of the animals. Young donkeys with good BCS were less affected than old donkeys. Lameness, poor coat condition, external parasites, abnormal mucous membrane and dental problems were observed in less than 30% of the animals. It was concluded that donkeys play a pivotal role economically and socially to the livelihoods of people in a peri-urban area (Joza) in terms of income generation and transportation. However, these animals are experiencing multiple health and welfare problems. Therefore, more access to veterinary services, training on donkey use and management, health and welfare promotion programs are of paramount importance in solving the problem of poor health and welfare in donkeys.
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  • Date Issued: 2014

A farm to fork approach to meat science

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