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Schalk Cloete   Dr.  Senior Scientist or Principal Investigator 
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Schalk Cloete published an article in April 2016.
11
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10
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12
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Distribution of Articles published per year 
(2003 - 2016)
Total number of journals
published in
 
6
 
Publications See all
Article 1 Read 0 Citations Evaluation of the OvineSNP50 chip for use in four South African sheep breeds L Sandenbergh, SWP Cloete, R Roodt-Wilding, MA Snyman, AE Be... Published: 05 April 2016
South African Journal of Animal Science, doi: 10.4314/sajas.v46i1.11
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Relatively rapid and cost-effective genotyping using the OvineSNP50 chip holds great promise for the South African sheep industry and research partners. However, SNP ascertainment bias may influence inferences from the genotyping results of South African sheep breeds. Therefore, samples from Dorper, Namaqua Afrikaner (NA), South African Merino (SA Merino) and South African Mutton Merino (SAMM) were genotyped to determine the utility of the OvineSNP50 chip for these important South African sheep breeds. After quality control measures had been implemented, 85 SA Merino, 20 Dorper, 20 NA and 19 SAMM samples remained, with an average call rate of 99.72%. A total of 49 517 (91.30%) SNPs on the chip met quality control measures and were included in downstream analyses. The NA had the fewest polymorphic loci, 69.20%, while the SAMM, Dorper and SA Merino had between 81.16% and 86.85% polymorphic loci. Most loci of the SA Merino, Dorper and SAMM had a MAF greater than or equal to 0.3. In contrast, the NA exhibited a large number of rare alleles (MAF < 0.1) and a uniform distribution of other loci across the MAF range (0.1 < MAF ≤ 0.5). The NA exhibited the least genetic diversity and had the greatest inbreeding coefficient among the four breeds. The results of the Dorper, SA Merino, and SAMM compare favourably with those of international breeds and thus demonstrate the utility of the OvineSNP50 chip for these breeds. Effects of SNP ascertainment bias, however, could be seen in the number of non-polymorphic loci and MAF distribution of the three commercial breeds in comparison with those of the NA. The implementation of methods to reduce the effect of SNP ascertainment bias and to ensure unbiased interpretation of genotype results should therefore be considered for future studies using OvineSNP50 chip genotype results.Keywords: Dorper, genome-wide, Merino, Namaqua Afrikaner, OvineSNP50, SA Mutton Merino, SNP
BOOK-CHAPTER 2 Reads 0 Citations Breeding breeding/breed, see also animal breeding in Developing Countries breeding/breed, see also animal breeding in de... SWP Cloete Published: 01 January 2013
Sustainable Food Production, doi: 10.1007/978-1-4614-5797-8_344
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Species breeding has led to marked genetic improvement of production by livestock in the developed world over the past decades. Selection has been so successful that the emphasis in the breeding objective has been changed to welfare, behavior, and other consumer-orientated objectives. The same level of progress has not been achieved in the developing world. Current and projected future population growth requires that food production from farm animals in these regions be improved markedly from the present inadequate levels. Limitations in the institutional infrastructure and the unique challenges of livestock production in the emerging world and the tropics were discussed in detail. This led to recommendations on how these challenges can be overcome and how “new” issues like global warming and animal welfare should be handled
Article 1 Read 0 Citations The fatty acid composition of muscles and fat depots of ostriches as influenced by genotype LC Hoffman, MM Brand, SWP Cloete, M Muller Published: 15 August 2012
South African Journal of Animal Science, doi: 10.4314/sajas.v42i3.7
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Three genotypes of ostrich (South African Black, Zimbabwean Blue Necks and crosses between Zimbabwean Blue Neck males x South African Black females) were used to investigate the influence of genotype on the fatty acid composition of the musculus gastrocnemius and musculus iliofibularis, and abdominal and breast fat depots. Total saturated fatty acids in both the m. gastrocnemius and m. iliofibularis were higher in crosses (36.4% and 35.9%) than in South African Black ostriches (32.9% and 30.4%), whereas mono-unsaturated fatty acids were highest in South African Black ostriches. Total polyunsaturated fatty acids in the m. gastrocnemius were lowest in South African Black ostriches (26.5%) compared with the Zimbabwean Blue Necks (33.2%). Neither the ratio of polyunsaturated to saturated (0.73 to 0.99) nor n-6 to n-3 (1.6 to 2.2) fatty acids were influenced by genotype, although the ratio of polyunsaturated to saturated fatty acids in Zimbabwean Blue Necks was higher in the m. gastrocnemius (0.99) than in the m. iliofibularis (0.73). Differences in individual fatty acids were prominent in the breast fat, and total saturated and mono-unsaturated fatty acids differed between genotypes in both breast and abdominal fat. Only the ratio of polyunsaturated to saturated fatty acids in the fat depots differed between South African Black (0.48) and Zimbabwean Blue Neck ostriches (0.42). The latter ratio was higher in the breast (0.50) than abdominal (0.42) fat in Zimbabwean Blue Necks. These results indicate that crossbreeding of different genotypes of ostriches reared under similar conditions does influence the overall fatty acid profiles of meat and fat.Keywords: Struthio camelus, SFA, MUFA, PUFA, crossbreeding
Article 2 Reads 1 Citation Short communication: Divergent selection for reproduction affects dag score, breech wrinkle score and crutching time in ... AJ Scholtz, JJE Cloete, ACM Kruger, SWP Cloete, JB van Wyk, ... Published: 15 August 2012
South African Journal of Animal Science, doi: 10.4314/sajas.v42i3.9
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Merino lines that were divergently selected from the same base population from 1986 to 2009 for their ability to rear multiples were assessed for dag score in autumn and spring, breech wrinkle score, and crutching time. Animals in the Low (L) line had higher dag and breech wrinkle scores and took longer to be crutched than High (H) line contemporaries. Expressed relative to H line least squares means, means of L line individuals were respectively 54%, 65%, 42% and 40% higher for autumn dag score, spring dag score, breech fold score, and crutching time. Gender effects for dag score were inconclusive, as ewe hoggets were more daggy than rams in autumn, with an opposite trend in spring. Shearer (n = 6) also affected crutching times, with an almost twofold difference in mean crutching time from the quickest shearer (27.7 ± 3.1 seconds) to the slowest shearer (49.4 ± 3.7 seconds). The inclusion of dag score and breech wrinkle score as linear covariates in an analysis on crutching time eliminated the effect of selection line. It thus seems that the quicker crutching times of H line animals may be related to line differences for dag score and, to a lesser extent, for breech wrinkle score.Keywords: Reproduction, selection lines, shearing time, wrinkle
BOOK-CHAPTER 2 Reads 0 Citations Breeding breeding/breed, see also animal breeding in Developing Countries breeding/breed, see also animal breeding in de... SWP Cloete Published: 01 January 2012
Encyclopedia of Sustainability Science and Technology, doi: 10.1007/978-1-4419-0851-3_344
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Species breeding has led to marked genetic improvement of production by livestock in the developed world over the past decades. Selection has been so successful that the emphasis in the breeding objective has been changed to welfare, behavior, and other consumer-orientated objectives. The same level of progress has not been achieved in the developing world. Current and projected future population growth requires that food production from farm animals in these regions be improved markedly from the present inadequate levels. Limitations in the institutional infrastructure and the unique challenges of livestock production in the emerging world and the tropics were discussed in detail. This led to recommendations on how these challenges can be overcome and how “new” issues like global warming and animal welfare should be handled
BOOK-CHAPTER 2 Reads 1 Citation Breeder Welfare: The Past, Present and Future S. W. P. Cloete, I. A. Malecki Published: 01 January 2011
Animal Welfare, doi: 10.1007/978-3-642-19297-5_2
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The welfare needs of mature ratite breeders are reviewed in this chapter. Ratite reproductive strategies and mate choice are discussed with reference to compatibility of breeding males and females housed in pairs. Past and present mating structures are discussed in terms of behaviour needs. It was shown that trauma is associated with the majority of cases where mature pair-bred ostrich breeding birds exit the breeding flock prematurely. It was noted that small (