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- Tarekegn, Getinet Mekuriaw, et al.
(författare)
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Genetic parameters of endocrine fertility traits based on in-line milk progesterone profiles in Swedish Red and Holstein dairy cows
- 2019
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 102, s. 11207-11216
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Tidskriftsartikel (refereegranskat)abstract
- Evaluating fertility traits based on endocrine progesterone profiles is becoming a promising option to improve dairy cow fertility. Several studies have been conducted on endocrine fertility traits, mainly in the Holstein breed. In this study, focusing also on the Swedish Red (SR) breed, genetic parameters were estimated for classical and endocrine fertility traits, the latter based on in-line milk progesterone records obtained for 14 Swedish herds using DeLaval Herd Navigator (DeLaval International, Tumba, Sweden). A total of 210,403 observations from 3,437 lactations of 1,107 SR and 1,538 Holstein cows were used. Mixed linear animal models were used for estimation of genetic parameters. Least squares means analysis showed that Holstein cows had a 2.5-d-shorter interval from calving to commencement of luteal activity (C-LA) and longer length of first inter-ovulatory interval (IOI) than SR cows. The highest mean interval for C-LA, IOI, and first luteal phase length (LPL) was observed in the fourth parity. The incidence of short (<18 d), normal, (18-24 d), and long (>24 d) IOI was 29.3, 40.7, and 30%, respectively. Genetic analysis indicated moderate heritability (h(2)) for C-LA (h(2) = 0.24), luteal activity during the first 60 d in milk (LA60, h(2) = 0.15), proportion of samples with luteal activity (PLA, h(2) = 0.13), and calving to first heat (CFH, h(2) = 0.18), and low heritability estimates for LPL (h(2) = 0.08) and IOI (h(2) = 0.03) in the combined data set for both breeds. Similar heritability estimates were obtained for each breed separately except for IOI and LPL in SR cows, for which heritability was estimated to be zero. Swedish Red cows had 0.01 to 0.06 higher heritability estimates for C-LA, LA60, and PLA than did Holstein cows. Calving interval had moderate heritability among the classical traits for Holstein and the combined data set, but h(2) was zero for SR. Commencement of luteal activity had a strong genetic correlation with LA60 (mean +/- SE; -0.88 +/- 0.06), PLA (-0.72 +/- 0.11), and CFH (0.90 +/- 0.04). Similarly, CFH had a strong genetic correlation with IOI (0.98 +/- 0.20). Number of inseminations per series showed a weak genetic correlation with all endocrine traits except IOI. Overall, endocrine traits had higher heritability estimates than classical traits in both breeds, and may have a better potential to explain the actual reproductive status of dairy cows than classical traits. This might favor inclusion of some endocrine fertility traits-especially those related to commencement of luteal activity as selection criteria and breeding goal traits if recording becomes more common in herds. Further studies on genetic and genomic evaluations for endocrine fertility traits may help to provide firm conclusions. A prerequisite is that the data from automatic devices be made available to recording and breeding organizations in the future and included in a central database.
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| 2. |
- Tarekegn, Getinet Mekuriaw, et al.
(författare)
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Genome-wide diversity and demographic dynamics of Cameroon goats and their divergence from east African, north African, and Asian conspecifics
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Indigenous goats make significant contributions to Cameroon's national and local economy, but little effort has been devoted to identifying the populations. Here, we assessed the genetic diversity and demographic dynamics of Cameroon goat populations using mitochondrial DNA (two populations) and autosomal markers (four populations) generated with the Caprine 50K SNP chip. To infer genetic relationships at continental and global level, genotype data on six goat populations from Ethiopia and one population each from Egypt, Morocco, Iran, and China were included in the analysis. The mtDNA analysis revealed 83 haplotypes, all belonging to haplogroup A, in Cameroon goats. Four haplotypes were shared between goats found in Cameroon, Mozambique, Namibia, Zimbabwe, Kenya, and Ethiopia. Analysis of autosomal SNPs in Cameroon goats revealed the lowest H-O (0.335 +/- 0.13) and H-E (0.352 +/- 0.15) in the North-west Highland and Central Highland populations, respectively. Overall, the highest H-O (0.401 +/- 0.12) and H-E (0.422 +/- 0.12) were found for Barki and Iranian goats, respectively. Barki goats had the highest average MAF, while Central Highland Cameroon goats had the lowest. Overall, Cameroon goats demonstrated high F-IS. AMOVA revealed that 13.29% of the variation was explained by genetic differences between the six population groups. Low average F-ST (0.01) suggests intermixing among Cameroon goats. All measures indicated that Cameroon goats are closer to Moroccan goats than to other goat populations. PCA and STRUCTURE analyses poorly differentiated the Cameroon goats, as did genetic distance, Neighbor-Net network, and neighbor-joining tree analyses. The haplotype analysis of mtDNA showed the initial dispersion of goats to Cameroon and central Africa from north-east Africa following the Nile Delta. Whereas, the approximate Bayesian computation indicated Cameroon goats were separated from Moroccan goats after 506 generations in later times (similar to 1518 YA), as supported by the phylogenetic net-work and admixture outputs. Overall, indigenous goats in Cameroon show weak phylogenetic structure, suggesting either extensive intermixing.
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| 3. |
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| 4. |
- Tarekegn, Getinet Mekuriaw
(författare)
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Morphological and molecular characterization of freshwater prawn of genus Macrobrachium in the coastal area of Cameroon
- 2019
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9, s. 14217-14233
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Tidskriftsartikel (refereegranskat)abstract
- Macrobrachium (Bate, 1868) is a large and cosmopolitan crustacean genus of high economic importance worldwide. We investigated the morphological and molecular identification of freshwater prawns of the genus Macrobrachium in South, South West, and Littoral regions of Cameroon. A total of 1,566 specimens were examined morphologically using a key described by Konan (Diversite morphologique et genetique des crevettes des genres Atya Leach, 1816 et Macrobrachium Bate, 1868 de Cote d'Ivoire, 2009, Universite d'Abobo Adjame, Cote d'Ivoire), leading to the identification of seven species of Macrobrachium: M. vollenhovenii (Herklots, 1857); M. macrobrachion (Herklots, 1851); M. sollaudii (De Man, 1912); M. dux (Lenz, 1910); M. chevalieri (Roux, 1935); M. felicinum (Holthuis, 1949); and an undescribed Macrobrachium species M. sp. To validate the genetic basis of the identified species, 94 individuals representing the species were selected and subjected to genetic characterization using 1,814 DArT markers. The admixture analysis revealed four groups: M. vollenhovenii and M. macrobrachion; M. chevalieri; M. felicinum and M. sp; and M. dux and M. sollaudii. But, the principal component analysis (PCA) separated M. sp and M. felicinum to create additional group (i.e., five groups). Based on these findings, M. vollenhovenii and M. macrobrachion may be conspecific, as well as M. dux and M. sollaudii, while M. felicinum and M. sp seems to be different species, suggesting a potential conflict between the morphological identification key and the genetic basis underlying speciation and species allocation for Macrobrachium. These results are valuable in informing breeding design and genetic resource conservation programs for Macrobrachium in Africa.
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| 5. |
- Tarekegn, Getinet Mekuriaw
(författare)
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Morphological Characterization of Goat Populations in Central Zone of Tigray, Ethiopia
- 2019
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Ingår i: Tropical animal science journal. - : Media Peternakan. - 2615-787X .- 2615-790X. ; 42, s. 81-89
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Tidskriftsartikel (refereegranskat)abstract
- Ethiopia has huge livestock resource, but poor in their productivity. It stated national small ruminant breeding policy and strategy focused on genetic improvement. This is intended to design appropriate breeding programs based on the indigenous breeds status. Study of phenotypic variation is among the prerequisite activities of genetic improvement that is limited in this study area. The objective of this study was to describe morphological characteristics and variations of goat populations in the Central zone of Tigray. Qualitative and quantitative data of 403 young to matured goats (326 lactating does and 77 bucks) were used to analyze by frequency procedure, GLM procedure, Pearson correlation, and multivariate analysis of SAS version 9.4. The study revealed that goats in Adwa district were distinct in coat colors and pattern, horn shape, ear orientation, head profile and ruff, significantly heavier (p<0.01) and larger (p<0.001) in height at withers and in height at pelvic than those in Tanqua Abergele (TA) and Kola Tembien (KT) districts. Goats found in Adwa district were morphologically distinct from those found in TA and KT districts with the higher discriminating values in female goats.
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