• Asian-Australasian Journal of Animal Sciences
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• 제23권2호
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• pp.188-196
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• 2010

The objective of this study was to characterize the litter sizes in Huanghuai goats with high prolificacy (HP, five or more kids born per litter on at least one occasion), and to compare their peripheral blood concentrations of progesterone and estradiol with those of goats with poor prolificacy (PP, up to three kids born per litter on any occasion). The circulating concentrations of progesterone and estradiol were measured by radioimmunoassay from daily blood samples taken during natural estrus cycles and at 1-5 days after ovariectomy. Estrus was synchronized using two doses of a prostaglandin analog. Litter size for the HP goats increased up to a parity of five and decreased thereafter. The percentage of goats with litter sizes of $\geq$4 from parities 3 to 6 ranged from 44.5% to 58.3%. Although small differences in litter size were obtained for goats of parities three, four and six relative to five, parity five does had the highest mean litter size. Progesterone concentrations began to rise earlier and were higher in the HP than in the PP goats on most days of the luteal phase, but not during the follicular phase of the cycle or after ovariectomy. There was a significant difference between the two groups (p<0.05) in the magnitude of the progesterone plateau. Mean estradiol concentrations in the HP group remained significantly higher than in the PP group (p<0.05) during the estrus cycle. There were two estradiol peaks in the HP goats during the early luteal phase, but only one in the PP group. Measurements of individual corpora lutea (CL) in vitro showed that there was a greater prevalence of small CL (<6 mm in diameter) in the HP group than in the PP group (p<0.05). After ovariectomy, the estradiol level on day 1 was significantly higher than at the nadir during the estrus cycle in both the HP (p<0.01) and PP (p<0.05) goats, while levels decreased by 12.3% and 26.2% respectively compared with the mid-luteal period in HP and PP goats (p<0.05). The overall mean estradiol concentrations in HP goats were lower than in the PP group, but no significant differences were found between groups at 1-5 days after ovariectomy.

• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.902-912
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• 2020

Objective: Mongolia is one of a few countries that supports over 25 million goats, but genetic diversity, demographic history, and the origin of goat populations in Mongolia have not been well studied. This study was conducted to assess the genetic diversity, phylogenetic status and population structure of Mongolian native goats, as well as to discuss their origin together with other foreign breeds from different countries using hypervariable region 1 (HV1) in mtDNA. Methods: In this study, we examined the genetic diversity and phylogenetic status of Mongolian native goat populations using a 452 base-pair long fragment of HVI of mitochondrial DNA from 174 individuals representing 12 populations. In addition, 329 previously published reference sequences from different regions were included in our phylogenetic analyses. Results: Investigated native Mongolian goats displayed relatively high genetic diversities. After sequencing, we found a total of 109 polymorphic sites that defined 137 haplotypes among investigated populations. Of these, haplotype and nucleotide diversities of Mongolian goats were calculated as 0.997±0.001 and 0.0283±0.002, respectively. These haplotypes clearly clustered into four haplogroups (A, B, C, and D), with the predominance of haplogroup A (90.8%). Estimates of pairwise differences (Fst) and the analysis of molecular variance values among goat populations in Mongolia showed low genetic differentiation and weak geographical structure. In addition, Kazakh, Chinese (from Huanghuai and Leizhou), and Arabian (Turkish and Baladi breeds) goats had smaller genetic differentiation compared to Mongolian goats. Conclusion: In summary, we report novel information regarding genetic diversity, population structure, and origin of Mongolian goats. The findings obtained from this study reveal that abundant haplogroups (A to D) occur in goat populations in Mongolia, with high levels of haplotype and nucleotide diversity.