• Korean Journal of Animal Reproduction
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• v.17 no.1
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• pp.27-34
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• 1993

The present study was conducted to examine the reproductive performance of dairy cow at alpine area. 1,515 dairy cows were managemented at above 800m of sea level around the Dea-Gwan Ryeong in Kangweon-Do. The results at this study were as follows ; 1. The average first estrus was 105.0 days after pastruation. 2. The highest percentage ofpregnancy(26.4%) and parturation(27.6%) were obtained at September to November and June to August, respectively. 3. The rate of pregnancy was 61.0%. Pregnancy rates according to insemination times of 1, 2 and 3 were 60.8, 23.5 and 9.8%, respectively and insemination time per pregnancy was 1.64. 4. Ages of first inseminatin, pregnancy and parturition of heifer were 17.9, 18.6 and 27.7 months, respectively. 5. Time of postpartum pregnancy was 133.0 days after parturition, and pregnancy period and calving interval were 279.6 and 410.3 days, respectively. 6. Six ratio of offspring was 52.1% of female versus 47.9% of male, and the proportion of twins was 0.65%. 7. The proportions of normal parturition, stillbirth and abortion were 91.9, 2.2 and 5.9%, respectively.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.295-303
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• 1994

The present study was conducted to examine the reprodutive performance and organs autopsy of culled dairy cows at alpine area. 795 culled dairy cows were managed and 206 culled dairy cows were examined by autopsy of reproductive organs at above 800m of sea level around the Daegwallryoung alpine area. The results of this study were at follows ; 1. Age and parity of culled dairy cows were 60.8 months and 3.0, respectively. 2. Age of first AI of heifer was 18.7 months, and age of pregnancy and parturition of heifer were 19.5 months and 28.6 months, respectively. 3. Al time per pregnancy was 1.7 and time of pregnancy after parturition, pregnancy period and calving interval were 140.9, 279.6 and 424.9 days, respectively. 4. Culled months after last parturition was 4.3 and the highest urogenital deseases of culled reason were 358(45.0%). 5. Reproductive organs deseases by autopsy were 120(58.4%), the highest ovary disease were 75(43.6%). 6. The highest ovary adhesions of reproductive organ diseases were 46(26.7%), infundibulum adhesion, obstruction of the oviduct and endometritis were 38(22.1%), 15(8.7%), and 14(8.2%), respectively. 7. In culled dairy cow for the reproductive organ disease, parity, age, culled months and AI number after last parturition were 3.2, 66.5 months, 7.9 months and 2.1, respectively.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.367-373
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• 1998

A survey was carried out to investigate the effect of the herd size on the reproductive traits of Hanwoo(Korean native cows). Data on the reproductive traits of 670 Korean native cows were collected from January, 1996 to December, 1997 and analyzed by the herd size. The results obtained were summarized as follows: 1. The average ages at first breeding were 437.9, 425.5 and 452.9 days in herd size 1 (less than 20 heads), 2 (21∼50 heads) and 3 (more than 51 heads), respectively (the over all average was 443.0 days). However, there was no significant difference between herd sizes (p＞0.05). 2. The average ages at first conception were 452.8, 438.4 and 467.1 days in herd size 1, 2 and 3, respectively (the over all average was 460.0 days). However, there was no significant difference between herd sizes (p＞0.05). 3. The average ages at first calving were 741.2, 730.2 and 755.9 days in herd size 1, 2 and 3, respectively (the over all average was 746.6 days). However, there was no significant difference between herd sizes (p＞0.05). 4. The average days to first estrus after calving was 70.1 days and it was shortest in herd size 3 (64.8 days) and longest in herd size 1(82.1 days). 5. The average numbers of services per conception were 1.54, 1.61 and 1.48 in herd size 1, 2, and 3, respectively (the over all average was 1.53). However, there was no significant difference between herd sizes (p＞0.05). 6. The average days to first conception after calving were 115.6, 99.1 and 80.6 days in herd size 1, 2 and 3, respectively (the over all average was 91.2 days). There was a trend that it was shorter as the herd size increased(p＜0.05). 7. The average length of calving interval was 375.3 days and it was shortest in herd size 3 (367. 4 days) and longest in herd size 1 (389.5 days).

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1550-1556
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• 2017

Objective: This study estimated the genetic parameters for productive and reproductive traits. Methods: The data included production and reproduction records of animals that have calved between 1979 and 2013. The genetic parameters were estimated using multivariate mixed models (DMU) package, fitting univariate and multivariate mixed models with average information restricted maximum likelihood algorithm. Results: The estimates of heritability for milk production traits from the first three lactation records were $0.03{\pm}0.03$ for lactation length (LL), $0.17{\pm}0.04$ for lactation milk yield (LMY), and $0.15{\pm}0.04$ for 305 days milk yield (305-d MY). For reproductive traits the heritability estimates were, $0.09{\pm}0.03$ for days open (DO), $0.11{\pm}0.04$ for calving interval (CI), and $0.47{\pm}0.06$ for age at first calving (AFC). The repeatability estimates for production traits were $0.12{\pm}0.02$, for LL, $0.39{\pm}0.02$ for LMY, and $0.25{\pm}0.02$ for 305-d MY. For reproductive traits the estimates of repeatability were $0.19{\pm}0.02$ for DO, and to $0.23{\pm}0.02$ for CI. The phenotypic correlations between production and reproduction traits ranged from $0.08{\pm}0.04$ for LL and AFC to $0.42{\pm}0.02$ for LL and DO. The genetic correlation among production traits were generally high (>0.7) and between reproductive traits the estimates ranged from $0.06{\pm}0.13$ for AFC and DO to $0.99{\pm}0.01$ between CI and DO. Genetic correlations of productive traits with reproductive traits were ranged from -0.02 to 0.99. Conclusion: The high heritability estimates observed for AFC indicated that reasonable genetic improvement for this trait might be possible through selection. The $h^2$ and r estimates for reproductive traits were slightly different from single versus multi-trait analyses of reproductive traits with production traits. As single-trait method is biased due to selection on milk yield, a multi-trait evaluation of fertility with milk yield is recommended.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1721-1728
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• 2018

Objective: The use of genetic markers can help to enhance reproduction in cattle, which is a very important trait for profitability in dairy production systems. This study evaluated the association between genotypes of leptin (LEP), toll-like receptor 4 (TLR4), and chemokine receptor of interleukin 8 C-X-C motif (CXCR1) genes and fertility traits in Czech Fleckvieh cattle. Methods: Phenotypic data from 786 Czech Fleckvieh cows raised on 5 farms in the Czech Republic were used, along with information from the 1st three parities. To determine genotype, the polymerase chain reaction-restriction fragment length polymorphism method was used. Results: Except for LEP g.-963C>T, all studied genotype frequencies of single nucleotide polymorphisms (SNPs) were distributed according to the Hardy-Weinberg equilibrium. Two LEP SNPs (g.-963C>T and c.357C>T) were associated with the age at the 1st calving, days open (DO), pregnancy rate after 1st service (PR), and calving interval (CLI). In LEP g.-963C>T the TT genotype heifers firstly calved 24 days earlier than CC genotype and the CT genotype cow showed a tendency for shorter DO and higher PR. In LEP c.357C>T we observed longer CLI and DO period in TT cows. In general, we can propose the TT genotype of g.-963C>T as favorable and the TT genotype of c.357C>T as unfavorable for a cow's fertility. Heterozygotes in TLR4 c.-226C>G were significantly associated with shorter CLI, and presented a nonsignificant tendency to be associated with higher PR. In CXCR1 c.777 C>G, we did not observe any relationship of this SNP with reproduction. Conclusion: Overall, the results showed that LEP could be an effective marker for improving reproduction in Czech Fleckvieh cattle. This study also provides novel insights into the relationship between TLR4 and CXCR1 SNPs and reproduction in dual-purpose cattle.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.83-91
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• 2024

We compared the reproductive performance, non-productive performance, and milk composition performance of two groups of lactating cows that were either rice straw or tall fescue. We also compared and analyzed these parameters after the first parturition during the breeding period. The calving interval, artificial insemination, and duration from calving to conception were longer in the rice straw group than in the tall fescue group. The 305-day and peak milk yields were significantly higher in the tall fescue group than in the rice straw group (p<0.01). Milk fat content was significantly higher in the tall fescue group than in the rice straw group (p<0.001), but milk protein content was the same between the feeding groups. The difference in raw milk sales income between rice straw and tall fescue groups tended to increase as the number of lactations increased, but there was no effect of reduced feed costs. Analysis of the milk production and raw milk sales income of the surveyed farms revealed that the average milk production per head was significantly (p<0.05) higher in the tall fescue group than in the rice straw group, and raw milk sales income showed a similar tendency. Overall, these results provide important details to be considered when selecting feed as a way to reduce milk production and heifer raising costs. However, there remains a need for future follow-up studies exploring the relationship between feed choice and the management of heifers.

• Journal of Animal Science and Technology
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• v.66 no.4
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• pp.682-701
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• 2024

This study estimated the heritabilities (h²) and genetic and phenotypic correlations between reproductive traits, including calving interval (CI), age at first calving (AFC), gestation length (GL), number of artificial inseminations per conception (NAIPC), and carcass traits, including carcass weight (CWT), eye muscle area (EMA), backfat thickness (BF), and marbling score (MS) in Korean Hanwoo cows. In addition, the accuracy of genomic predictions of breeding values was evaluated by applying the genomic best linear unbiased prediction (GBLUP) and the weighted GBLUP (WGBLUP) method. The phenotypic data for reproductive and carcass traits were collected from 1,544 Hanwoo cows, and all animals were genotyped using Illumina Bovine 50K single nucleotide polymorphism (SNP) chip. The genetic parameters were estimated using a multi-trait animal model using the MTG2 program. The estimated h² for CI, AFC, GL, NAIPC, CWT, EMA, BF, and MS were 0.10, 0.13, 0.17, 0.11, 0.37, 0.35, 0.27, and 0.45, respectively, according to the GBLUP model. The GBLUP accuracy estimates ranged from 0.51 to 0.74, while the WGBLUP accuracy estimates for the traits under study ranged from 0.51 to 0.79. Strong and favorable genetic correlations were observed between GL and NAIPC (0.61), CWT and EMA (0.60), NAIPC and CWT (0.49), AFC and CWT (0.48), CI and GL (0.36), BF and MS (0.35), NAIPC and EMA (0.35), CI and BF (0.30), EMA and MS (0.28), CI and AFC (0.26), AFC and EMA (0.24), and AFC and BF (0.21). The present study identified low to moderate positive genetic correlations between reproductive and CWT traits, suggesting that a heavier body weight may lead to a longer CI, AFC, GL, and NAIPC. The moderately positive genetic correlation between CWT and AFC, and NAIPC, with a phenotypic correlation of nearly zero, suggesting that the genotype-environment interactions are more likely to be responsible for the phenotypic manifestation of these traits. As a result, the inclusion of these traits by breeders as selection criteria may present a good opportunity for developing a selection index to increase the response to the selection and identification of candidate animals, which can result in significantly increased profitability of production systems.

• Animal Bioscience
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• v.35 no.10
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• pp.1499-1511
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• 2022

Objective: This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods: The data of 25,789 test-day milk yield and milk composition records of 1,468 cattle from lactation 1 to 3 of Holstein Friesian (HF) and crossbred HF dairy cattle calved between 1990 and 2015 from three government research farms in Thailand were analysed. 305-day milk yield was estimated by the Wood model and a test interval method. The Wood model was used for estimating cumulative 305-day milk yield, peak milk yield, days to peak milk yield and persistency. Genetic parameters were estimated using linear mixed models with herd, breed group, year and season of calving as fixed effects, and animals linked to a pedigree as random effects, together with a residual error. Univariate models were used to estimate variance components, heritability, estimated breeding values (EBVs) and repeatability of each trait, while pairwise bivariate models were used to estimate covariance components and correlations between traits in the same lactation and in the same trait across lactations. Results: The heritability of 305-day milk yield, peak milk yield and protein percentage have moderate to high estimates ranging from 0.19 to 0.45 while days to peak milk yield, persistency and fat percentage have low heritability ranging from 0.08 to 0.14 in lactation 1 cows. Further, heritability of most traits considered was higher in lactation 1 compared with lactations 2 and 3. For cows in lactation 1, high genetic correlations were found between 305-day milk yield and peak milk yield (0.86±0.07) and days to peak milk yield and persistency (0.99±0.02) while estimates of genetic correlations between the remaining traits were imprecise due to the high standard errors. The genetic correlations within the traits across lactation were high. There was no consistent trend of EBVs for most traits in the first lactation over the study period. Conclusion: Both the Wood model and test interval method can be used for milk yield estimates in these herds. However, the Wood model has advantages over the test interval method as it can be fitted using fewer test-day records and the estimated model parameters can be used to derive estimates of other lactation curve parameters. Milk yield, peak milk yield and protein percentage can be improved by a selection and mating program while days to peak milk yield, persistency and fat percentage can be improved by including into a selection index.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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• pp.60-67
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• 2000

A survey involving 71 cattle and buffalo farming households under coconut plantations was carried out in three districts (Pannala, Bingiriya and Kuliyapitiya) with the aim of assessing the status of livestock farming. Also, 24 households (eight from each district) were visited monthly for period of one year to collect information on feeding practices. Apart from milk, animals were reared for selling, draught, bio-gas and for manure. Due to difference in system of management of cattle and buffaloes, manure from buffaloes (46%) was more frequently used for coconuts than that from cattle (10%). Majority of cattle were improved breeds (temperate origin) or their crosses, as compared to buffaloes (mainly indigenous). The most predominant management system was tethered grazing during the day, and stall feeding during the night. Coconut land (own or others) and paddy fields were the major grazing areas for the animals. The grass from coconut land was lower in crude protein (8.2%) and digestibility (48%) compared to those from paddy fields (12.1 and 57%, respectively). Of the 288 rations analysed, grass was included in 280 of the daily rations for cattle as compared to 251 for buffaloes. Straw was more commonly included in mixed rations for buffaloes (137 out of 288) than for cattle (53 out of 288). The frequency of use of straw for buffaloes was high in Pannala (75 out of 137 cases). There was wide variation among the improved breeds of cattle and buffaloes in milk production (2 to 9 litres/day), lactation length (6 to 10 months) and calving interval (13-21 months).

• Journal of Embryo Transfer
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• v.25 no.1
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• pp.21-27
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• 2010

The increase in the total number of cows on farms, which breed Korean Native Cattle (KNC), is associated with many problems. In particular, the services per conception and calving interval have increased. In this study, we examined the effect of dietary supplementation with vitamin and mineral complex on the estrus rate, pregnancy rate, gestation length, and birth weight of KNC calves. Multiparous or primiparous KNC were divided into 3 groups with 40 heads per group. Experimental group 1 was administered a consisting of 35,000 IU vitamin A, 100 IU vitamin E, 200 mg $\beta$-carotene, 200 mg Zn methionine, and 1.5 mg Se. Experimental group 2 was administered a vitamin complex (100 g/day) consisting of 100 IU vitamin E and 200 mg $\beta$-carotene. In the case of multiparous KNC, the estrus detection rate in the control group was 90.0% and those in the experimental groups were 75.0% to 95.0%. However, the first-service pregnancy rate after parturition in the control group was 41.2%, which was significantly lower than that in the experimental groups (71.0% to 76.7%; p<0.05). The average duration of pregnancy in the group supplemented with the vitamin complex was days, which was similar to that in the case of the control group. The birth weight of calves from cows fed with vitamin complex was 25.3 to 27.0 kg, which was similar to that in the case of the control group (25.2 to 26.0 kg). In the case of primiparous KNC, no differences in the estrus rate, pregnancy rate, gestation length, or the birth weight of calves were noted between the groups. Thus, dietary supplementation vitamin and mineral complex have no effect on the reproductive efficiency in primiparous cows, but the pregnancy rate was observed to have increased in multiparous KNC with these supplements.