• Asian-Australasian Journal of Animal Sciences
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• 제17권1호
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• pp.18-26
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• 2004

This study evaluated the impact of an AI heifer calf rearing scheme on dairy stock development, in a coconut grazing and a peri-urban smallholder dairy production system in the Western Province of Sri Lanka. The heifer rearing scheme included free advice on calf rearing, drugs, acaricides, minerals and subsidised concentrates for 30 months. The farmers in the coconut growing area integrate dairying with their plantation, they sell their milk to the main processors. The peri-urban farmers are intensive milk producers, who sell their milk at informal markets. To estimate the effect of the heifer rearing scheme on dairy replacement stock development, scheme farmers were compared with farmers who did not participate in the scheme. Calf mortality was twice as high in non-scheme farms (23-28%) as in scheme farms (12-14%). The scheme had a positive effect on weight development and scheme heifers calved 4.5 months earlier than non-scheme heifers. The calf rearing package is cost effective in both farming systems, however, the required cash inputs are a major constraint. The costs per in-calf heifer under the scheme are much lower than the production of such animals by either multiplication in state farms or importing them. The coconut grazing system showed the highest potential for producing surplus dairy stock.

• 농업과학연구
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• 제46권1호
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• pp.27-31
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• 2019

It is well documented that intensive selection in dairy cattle for economic value such as increased milk yield led to a decline in reproductive performance. Recent studies using genome-wide association studies (GWASs) discovered candidate genes involved in the lower fertility including embryo development and conception rates. However, the information, which showed a lower reproductive performance, is limited to dairy cattle, especially Holstein, and the candidate genes were not examined in the Korean native cattle Hanwoo which has been intensively selected and bred for meat in the last few decades. We selected the candidate genes WBP1 and PARM1 reported to be associated with cow and/or heifer conception in dairy cattle and analyzed the genotype because those genes have non-synonymous single nucleotide polymorphisms (SNPs). To determine the single base change, we used the high resolution melting (HRM) assay which is rapid and cost-effective for a small number of genes. We found that most heifers with higher conception (1: service per conception) have the AA genotype coding Threonine rather than Proline in the WBP1 gene. We did not detect an association for a SNP in PARM1 in our analysis. In conclusion, the genetic variation of WBP1 can be used as a selective marker gene to improve reproductive performance, and HRM assay can be used to identify common SNP genotypes rapidly and cost effectively.

• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1318-1328
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• 2011

The tropics is not an ideal location for calf rearing as the high temperatures and humidities introduce many potential disease problems to milk fed calves. In addition, the type of dairy farming (generally poorly resourced small holder farming) and the general lack of awareness of the long term implications of poorly reared stock do not encourage farmers to pay close attention to their calf and heifer rearing systems. Surveys of calf rearing systems in Asia, tropical Africa and South America highlight the high calf and heifer mortalities. A range of 15 to 25% pre-weaning calf mortality is typical on many tropical dairy farms. It is often as high as 50%, indicating very poor calf management. This contrasts with US findings of less than 8% mortality from birth to 6 months while surveys of Australian farmers report only 3% losses. Simple extension programs on farms in Sri Lanka and Kenya have drastically reduced calf mortalities and improved pre-weaning growth rates. Improved management strategies leading to lower calving intervals, higher calving rates, reduced still born and pre-weaned calf mortalities and fewer non pregnant heifers can supply many more dairy herd replacements than currently occurs. Such strategies can increase the number of replacement heifer calves in the herd from 15 to over 35%, thus allowing farmers to increase their herd sizes through natural increases. Simple management procedures such as ensuring adequate intake of good quality colostrum within the first 12 hours of life, housing and good hygiene to minimise disease transfer, providing clean drinking water, developing appropriate feeding protocols to encourage early rumen development and paying closer attention to climate control and animal health can all lead to improved calf vigour and performance. Good record keeping is also important so farmers can more easily identify susceptible calves and quickly treat potential problems.

• 한국가축번식학회지
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• 제17권4호
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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.

• Journal of Animal Science and Technology
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• 제49권1호
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• pp.137-146
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• 2007

2005년 말을 기준으로 우리나라의 농림업 생산액은 총 36.3조원으로 이중 축산업 생산액은 11.8조원으로 전체 생산액의 32.5%를 차지하여 가장 많은 비율을 점유하고 있으며(농림부, 2006), 유제품의 소비량도 꾸준히 증가하여 1인당 63.6kg의 우유․유제품을 섭취하는 것으로 나타났다(농촌경제연구원, 2005). 이 같은 성장은 축산농가들이 국제 경쟁력 확보를 위해 그동안 보여준 각고의 노력과 꾸준한 투자의 결과로 평가되고 있으며, 이제는 축산물이 국민의 식생활에서 없어서는 안될 중요한 위치를 차지하게 되었다. 우리나라의 가축사육두수는 1970년대부터 해마다 계속 증가하여 2005년 말 현재 한우 1,819천두, 젖소 479천두, 돼지 8,962천두, 닭 109,628천수가 사육되고 있으며 사육농가의 전업화로 인하여 농가수는 점차 줄어들고 있는 반면에 농가당 사육두수는 증가하고 있는 실정이다(농림부, 2005). 농가당 평균 가축사육두수는 한우 8.8두, 젖소 51.7두, 돼지 671.4두, 닭 813.0수이며, 이중 부업이 아닌 전업농으로 볼 수 있는 한우 50두 이상의 사육농가가 전체 한우농가의 2.9%, 젖소 50두 이상 사육농가가 46.8%, 돼지 1,000두 이상의 농가가 21.6%, 닭 30,000수 이상의 농가가 1.0%를 차지하고 있어, 젖소가 다른 축종에 비해 전업농의 규모가 가장 많이 이루어졌다고 볼 수 있다(농림부, 2005). 따라서 매년 축산농가로부터 발생되는 분뇨의 양도 증가되고 있으며, 1990년초부터는 가축분뇨가 작물의 비료원으로 쓰이는 순기능보다는 환경오염의 한 요인으로 지목되면서 토양, 수질 및 대기오염이라는 역기능이 더 부각됨에 따라 도시근교의 낙농가, 초지나 사료작물포를 확보하지 못한 목장, 상수원 보호구역내에 위치한 목장에서는 분뇨처리에 고심을 하지 않을 수 없게 되었다. 특히 체격이 크고 방목지 및 운동장 등의 야외에서 사육되는 경우가 많은 젖소는 다른 가축에 비해 분뇨배설량이 많을 뿐 아니라, 운동장 등 축사 외부에서 활동하는 시간이 많기 때문에 주변으로부터 환경을 오염시키는 주범으로 지목을 받아 왔다. 또한 조사료 생산기반인 동시에 생산된 분뇨를 환원해야 할 경지면적이 협소한 상황에서 이루어진 젖소의 규모확대는 가축분뇨의 토양에 대한 부하를 높이게 되었고, 하천의 수질을 오염시키는 환경오염의 주범으로 인식되어 왔다. 이와같은 대내외적인 요인으로 인해 낙농가들은 목장의 규모에 관계없이, 분뇨를 적절하게 처리하는 것이 목장관리에 필수적인 사항으로 인식하게 되었다. 가축분뇨는 2, 3차 산업에서 발생하는 폐기물과는 그 성격 자체가 판이하게 달라 제도적 접근 방식도 나라와 환경에 따라 현격하게 다르다. 미국과 EC의 경우는 가축분뇨 자체를 환경보전재(Natural Resource)로 규정하고 적정한 사용방법을 정립하여 계도(Guide) 하므로서 환경을 보전하는 적극적인 환경보전 제도를 채택하고 있으며, 일본의 경우는 방류수의 수질을 규제하는 소극적 환경보전 제도로 출발했으나 1993년부터는 환경보전형 농업(축산)으로 정책방향을 전환하여 실행해 오고 있다. 우리나라도 이미 1981년부터 가축분뇨에 의한 환경오염 방지제도(법)가 시행되어 왔으나 법의 시행으로부터 25년이 경과한 현재까지도 가축분뇨에 의한 환경오염은 사회로부터 계속 지탄을 받고 있는 상태이다. 가축분뇨의 처리방식은 축종이나 농가 경영여건별로 크게 다르나, 궁극적으로는 경작지에 퇴비․액비 형태로 살포하여 이용하거나 또는 정화하여 방류하는 방법으로 이루어지고 있다. 따라서 젖소분뇨 또는 슬러리 처리에 필요한 시설 또는 활용계획을 세우기 위해서는 젖소로부터 배출되는 분뇨의 특성뿐만 아니라 오염물질 및 비료성분 배출량 추정이 무엇보다 중요하다고 할 수 있다. 본 연구는 젖소분뇨를 효율적이고 적절하게 처리하기 위한 기초자료를 제공하고 국가단위 관리방안을 제시하기 위하여 수행하였다.

• 한국수정란이식학회지
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• 제31권3호
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• pp.261-265
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• 2016

The aim of the present study was to evaluate and estimate timing of artificial insemination (AI) in Hanwoo heifer (Korean native cattle) that is the most popular breed of beef cattle in Korea. To determine changes in body weight of heifers around AI, body weight were measured at different stages either before or after AI. We found that daily body weight gain was higher in the pregnant cows after AI. We also investigate correlation between body mass measured by shoulder height and body length, and conception rates, used (body length+ height)2 instead of height2 for body mass index (BMI), and found that relatively more BMI heifers (>55) showed higher conception rates. Finally, we estimated body weight by measuring should height (SH), heart girth (HG), and body length (BL); $BW=3.93372^*HG-2.90985^*SH-0.021^*BL$. In addition, we observed that HG is most closely correlated with BW; $y(BW)=1.77355^*x(HG)$, $R^2=0.98881$. In summary, we can determine the best timing of AI using body measurement and its application including BMI.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1338-1350
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• 2012

This review focuses on the nutritional effects from birth until age at first calving on growth, mammary developmental changes, and first-lactation milk yield in heifer calves. The advancement in the genetic potential and the nutritional requirements of the animals has hastened the growth rate. Genetic selection for high milk yield has suggested higher growth capacity and hence increasing nutritional inputs are required. Rapid rearing by feeding high energy or high concentrate diets not only reduces the age of sexual maturity but also lowers the time period of attaining the age of first calving. However, high energy diets may cause undesirable fat deposition thereby affecting future milk yield potential. Discrepancies exist whether overfed or overweight heifers at puberty can influence the mammary development and future milk yield potential and performance. The data on post-pubertal nutritional management suggested that body weight at calving and post-pubertal growth rate is important in first lactation milk yield. There is a continuous research need for strategic feeding that accelerates growth of dairy heifers without reduction in subsequent production. Nutritional management from birth, across puberty and during pregnancy is critical for mammary growth and for producing a successful cow. This review will mostly highlight studies carried out on dairy breeds and possible available opportunities to manipulate nutritional status from birth until age at first calving.

• 한국수정란이식학회지
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• 제31권3호
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• pp.255-260
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• 2016

The aim of this study is to evaluate the effects of vitamin or mineral supplements on the conception rates of dairy heifers when replacing the last injection of GnRH with hCG in ovsynch protocol (experiment 1) and also to investigate whether the estrus synchronization treatment in the heifer stage affects the conception rates after $1^{st}$ parturition (experiment 2). In experiment 1, 50 heifers were randomly assigned into 3 groups: 20 heifers each in groups 1 and 2, and 10 in group 3. All three groups were treated with an intramuscular injection of GnRH on day 0 (day 0 = the day of program start), $PGF_{2{\alpha}}$ on day 7 and hCG on day 9, and were inseminated on day 10, 12~16h after hCG injection. In group 1 (vitamin group), the heifers were treated with an intramuscular injection of 5 ml of vitamin-ADE $500^{(R)}$, and group 2 (mineral group) was treated twice with an intramuscular injection of 30 ml of mineral supplement-LAPTOVET$^{(R)}$ on a one-week interval beginning on the day of hormone treatment (day 0 and day 7 respectively). Group 3 (control) was treated only with hormones. Pregnancy diagnosis was performed by ultrasonography through a rectal probe. First service conception rates (FSCR) and average services per conception (ASPC) were recorded for all subjects. Of the total 50 heifers, 6 (2 in group 1, 3 in group 2, and 1 in group 3) heifers were eliminated due to accidents during experiment 1. FSCRs were 58.8% (10/17), 66.7% (12/18) and 44.4% (4/9) in groups 1, 2 and 3, respectively. ASPCs were $1.53{\pm}0.72$, $1.27{\pm}0.59$ and $1.63{\pm}0.74$ in groups 1, 2 and 3, respectively. Although there were no significant difference between the groups, relatively good results (higher FSCR and lower ASPC) were obtained in both group 1 and 2. In experiment 2, 11 primiparous cows from group 2 of experiment 1 in heifer stage which had been treated both with the hormones for estrus synchronizing and mineral supplements (ES group), and 12 primiparous cows treated only with minerals (non-ES group) were compared to examine the effects of estrus synchronization program on conception rates after $1^{st}$ parturition. Following the examination, postpartum ASPCs were $1.55{\pm}0.82$ and $2.17{\pm}1.47$ in ES group and non-ES group, respectively. The postpartum average days open (ADO) were $116{\pm}56$ and $197{\pm}93$ in ES group and non-ES group, respectively. Although there were no significant difference between the two groups, desirable results (lower ASPC and shorter ADO) were found in ES group after $1^{st}$ parturiton. In conclusion, experiment 1 indicates that vitamin or mineral supplement with ovsynch protocol may have some positive effect on FSCR and ASPC of dairy heifers, and in experiment 2, ES program in heifer stage had a positive effect on ASPC and ADO following $1^{st}$ parturition.

• Asian-Australasian Journal of Animal Sciences
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• 제33권8호
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• pp.1360-1368
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• 2020

Objective: The aim of our study was to determine the associations of heifer reproductive performance with survival up to the first calving, first-lactation milk yield, and the probability of being culled within 50 days after first calving. Methods: Data from 33 large Holstein-Friesian commercial dairy herds were gathered from the official milk recording database in Hungary. The data of heifers first inseminated between January 1, 2011 and December 31, 2014 were analyzed retrospectively, using Cox proportional hazards models, competing risks models, multivariate linear and logistic mixed-effects models. Results: Heifers (n = 35,128) with younger age at conception were more likely to remain in the herd until calving, and each additional month in age at conception increased culling risk by 5.1%. Season of birth was related to first-lactation milk yield (MY1; n = 19,931), with cows born in autumn having the highest milk production (p<0.001). The highest MY1 was achieved by heifers that first calved between 22.00 and 25.99 months of age. Heifers that calved in autumn had the highest MY1, whereas calving in summer was related to the lowest milk production (p<0.001). The risk of culling within 50 days in milk in first lactation (n = 21,225) increased along with first calving age, e.g. heifers that first calved after 30 months of age were 5.52-times more likely to be culled compared to heifers that calved before 22 months of age (p<0.001). Calving difficulty was related to higher culling risk in early lactation (p<0.001). Heifers that required caesarean section were 24.01-times more likely to leave the herd within 50 days after first calving compared to heifers that needed no assistance (p<0.001). Conclusion: Reproductive performance of replacement heifers is closely linked to longevity and milk production in dairy herds.

• Animal Bioscience
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• 제34권5호
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• pp.855-866
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• 2021

Objective: Performance and physiological responses of dairy calves may change by using extruded soybean meal (ESBM) instead of common soybean meal (SBM) in starter feed. The aims of the current study were i) to determine the effect of extrusion processing of SBM on protein electrophoretic size, fourier transform infrared spectroscopy (FTIR) structures and Cornell Net Carbohydrate and Protein System (CNCPS) protein subfractions and ii) to determine the effect of substitution of SBM with ESBM in starter feed of Holstein heifer calves during pre and post-weaning on performance, nutrient digestibility, and blood metabolites. Methods: The SBM was substituted with ESBM at the level of 0%, 25%, 50%, 75%, and 100% (dry matter [DM] basis). Fifty heifer calves (initial body weight 40.3±0.63 kg) were used for the study. After birth, animals were fed colostrum for 3 days and then they were fed whole milk until weaning. Animals had free access to starter feed and water during the study. Results: Extrusion of SBM decreased electrophoretic protein size and increased rapidly degradable true protein fraction, changed FTIR protein and amide II region. With increasing level of ESBM in the diet, starter intake increased quadratically during the pre-weaning period (p<0.05) and body weight, DM intake and average daily gain increased linearly during the post-weaning and the whole study period (p<0.05). Tbe DM and crude protein digestibilities at week 14 and blood glucose and beta hydroxybutyric acid increased linearly in calves as the level of ESBM increased in the diet (p<0.05). Conclusion: Dairy calves performance and physiological responses were sensitive to SBM protein characteristics including electrophoretic size, FTIR structures and CNCPS protein fractions.