• Asian-Australasian Journal of Animal Sciences
• /
• 제33권9호
• /
• pp.1369-1377
• /
• 2020

Objective: The main objectives of the present study were to assess the genetic diversity, population structure and to appraise the efficiency of ongoing selective breeding program in the closed nucleus herd of Nellore sheep through pedigree analysis. Methods: Information utilized in the study was collected from the pedigree records of Livestock Research Station, Palamaner during the period from 1989 to 2016. Genealogical parameters like generation interval, pedigree completeness, inbreeding level, average relatedness among the animals and genetic conservation index were estimated based on gene origin probabilities. Lambs born during 2012 and 2016 were considered as reference population. Two animal models either with the use of F_i or ΔF_i as linear co-variables were evaluated to know the effects of inbreeding on the growth traits of Nellore sheep. Results: Average generation interval and realized effective population size for the reference cohort were estimated as 3.38±0.10 and 91.56±1.58, respectively and the average inbreeding coefficient for reference population was 3.32%. Similarly, the effective number of founders, ancestors and founder genome equivalent of the reference population were observed as 47, 37, and 22.48, respectively. Fifty per cent of the genetic variability was explained by 14 influential ancestors in the reference cohort. The ratio f_e/f_a obtained in the study was 1.21, which is an indicator of bottlenecks in the population. The number of equivalent generations obtained in the study was 4.23 and this estimate suggested the fair depth of the pedigree. Conclusion: Study suggested that the population had decent levels of genetic diversity and a non-significant influence of inbreeding coefficient on growth traits of Nellore lambs. However, small portion of genetic diversity was lost due to a disproportionate contribution of founders and bottlenecks. Hence, breeding strategies which improve the genetic gain, widens the selection process and with optimum levels of inbreeding are recommended for the herd.

• 한국임상수의학회지
• /
• 제8권1호
• /
• pp.47-52
• /
• 1991

A total of 2,024 quarters of 515 dairy cattle in Kangweon area were examined for incidence of subclinical mastitis. Milk samples from cattle infected with subclinical mastitis were studied bacteriologically and the bacterial strains isolated were further examined for sensitivity to 12 antibacterial agents. And the status of carrying out the mastitis control program in 28 dairy farms was examined. The results obtained were summerized as follows ; 1. A total of 308(59.8%) of 515 cattle and 656(32.4%) of 2,024 quarters were found to be infected with subclinical mastitis. 2. The 277 strains of etiological agents were isolated from 358 subclinical quarters. These were identified as Staphylococcus aureus(14.4%), other staphylococci(36.5%), Streptoccus agalatiae(8.7%), other streptococci(30.7%), Bacillus spp.(1.8%), Corynebacterium spp.(1.4%) and coliform(0.7%). 3. The 109 strains of streptococci and 141 strains of staphylococci were examined for sensitivity to 12 antibacterial agents. All the strains of streptococci were sensitive to penicillin, ampicillin and cephalothin, and they were also sensitive to erythromycin(88.1%), clindamycin(83.5%), enrofloxacin(75.2%), trimethoprim＋sulfamethoxazole(67.9%), The strains of staphylococci were sensitive to cephalothin(97.2%), gentamicin(83.0%). enroflozacin(80.9%), trimethoprim＋sulfamethoxazole(78.0%), erythromycin(71.6%) and clindamycin(71.6%). But all the strains resisted to colistin. 4. In the 28 dairy farms examined, condition of udder before washing was dirty in most of the farms (89.7%). Hygiene of milking equipment was only good in the 5 farms(17.9%). Teat preparation before milking was good in the 6 farms(21.4%). The farms in which teat dipping after milking was conducted were 46.4%. Dry cow treatment for the complete herd was carried out in most of the farms(89.3%) but mastitis checking was only carried out in the 8 farms(28.6%) irregularly.

• 한국수정란이식학회지
• /
• 제30권4호
• /
• pp.265-270
• /
• 2015

Growth rate during rearing, which varies depending on provided nutrition, has been related with age at $1^{st}$ calving (AFC). This study investigated the effect of upgrowth parameters during the rearing period on the reproduction of nulliparous Holstein heifers. The study comprised 77 successively born heifers from the same herd. Growth rate and fertility traits were measured during rearing and fertility parameters were recorded in lactations 1. Growth parameters (body weight, height, heart girth and body length) were measured at the approximate birth time, 270 and 450 d of age. Reproduction data collected included age at $1^{st}$ breeding, number of services per conception (S/C), pregnancy rate to $1^{st}$ artificial insemination, AFC. Animals were subsequently divided into 4 AFC groups for analysis: <23 mo, 23~25 mo, 26~30 mo and >30 mo. The AFC reflected both upgrowth rate and heifer reproduction, with later calving heifers smaller. Increased skeletal growth (at 270 and 450 d) was related with a reduced AFC (p<0.05). Early calving animals (<23 mo) had the best reproduction as nulliparous heifers, with most conceiving at first service (87.5%). Fertility in the first lactation was the worst in the oldest AFC group (>30 mo). In the 1st lactation period, a number of services per conception ($3.1{\pm}0.3$) increased with increasing AFC (>30 mo). Sub-optimal upgrowth related with an increased AFC could be mitigated by improved monitoring of replacement heifers during the rearing period.

• 대한수의학회지
• /
• 제14권2호
• /
• pp.253-268
• /
• 1974

A total of 331 dairy cattle in Jeonnam area were examined for the breeding status and hematological values during the period from June to August. 1971 and 1974. The data obtained were analysed according to the status of breeding and the type of farm management. The results obtained in this work were summarized as follows: 1. 331 dairy cows were grouped as pregnant (63.81%) anestrus after parturition (12.45%), pregnancy unknown (11.48%), repeat breeder (10.32%), and others (1.94%). 2. The summery of reproductive histories and clinical examination were as follows. Average of calving interval was 16.5 months, interval from parturition to first breeding 97 days and postpartum interval to first estrus 72 days. Services per conception was 1.6 rate of postpartum estrus (60 days) 12.0%, and the rate of repent breeder 10.3%. 3. Generally, the blood values of RBC, Hb, serum total protein and A/G ratio were lower than those normal values, especially, the cows which showed abnormal values belonged to the repeat breeder and the unknown to conception group. The mean value for serum inorganic phosphorus was the normal value or hyperphosphatemia, on the other hand, the mean value for serum calcium of the repeat breeder group was the lowest than the other group. 4. Follow-up evaluations on the results of the laboratory tests strongly suggest that the problems of repeat breeder had a tendency to occur more frequently in the large herd (A and B type farm), and the Ca/P ratio of almost all the cows showed abnormal values.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권4호
• /
• pp.508-518
• /
• 2019

Objective: This research aimed to determine biological pathways and protein-protein interaction (PPI) networks for 305-d milk yield (MY), 305-d fat yield (FY), and age at first calving (AFC) in the Thai multibreed dairy population. Methods: Genotypic information contained 75,776 imputed and actual single nucleotide polymorphisms (SNP) from 2,661 animals. Single-step genomic best linear unbiased predictions were utilized to estimate SNP genetic variances for MY, FY, and AFC. Fixed effects included herd-year-season, breed regression and heterosis regression effects. Random effects were animal additive genetic and residual. Individual SNP explaining at least 0.001% of the genetic variance for each trait were used to identify nearby genes in the National Center for Biotechnology Information database. Pathway enrichment analysis was performed. The PPI of genes were identified and visualized of the PPI network. Results: Identified genes were involved in 16 enriched pathways related to MY, FY, and AFC. Most genes had two or more connections with other genes in the PPI network. Genes associated with MY, FY, and AFC based on the biological pathways and PPI were primarily involved in cellular processes. The percent of the genetic variance explained by genes in enriched pathways (303) was 2.63% for MY, 2.59% for FY, and 2.49% for AFC. Genes in the PPI network (265) explained 2.28% of the genetic variance for MY, 2.26% for FY, and 2.12% for AFC. Conclusion: These sets of SNP associated with genes in the set enriched pathways and the PPI network could be used as genomic selection targets in the Thai multibreed dairy population. This study should be continued both in this and other populations subject to a variety of environmental conditions because predicted SNP values will likely differ across populations subject to different environmental conditions and changes over time.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권3호
• /
• pp.334-340
• /
• 2019

Objective: The objective of this study was to investigate the genetic components of daily milk yield and to re-rank bulls in South Korea by estimated breeding value (EBV) under heat stress using the temperature-humidity index (THI). Methods: This study was conducted using 125,312 monthly test-day records, collected from January 2000 to February 2017 for 19,889 Holstein cows from 647 farms in South Korea. Milk production data were collected from two agencies, the Dairy Cattle Genetic Improvement Center and the Korea Animal Improvement Association, and meteorological data were obtained from 41 regional weather stations using the Automated Surface Observing System (ASOS) installed throughout South Korea. A random regression model using the THI was applied to estimate genetic parameters of heat tolerance based on the test-day records. The model included herd-year-season, calving age, and days-in-milk as fixed effects, as well as heat tolerance as an additive genetic effect, permanent environmental effect, and direct additive and permanent environmental effect. Results: Below the THI threshold (${\leq}72$; no heat stress), the variance in heat tolerance was zero. However, the heat tolerance variance began to increase as THI exceeded the threshold. The covariance between the genetic additive effect and the heat tolerance effect was -0.33. Heritability estimates of milk yield ranged from 0.111 to 0.176 (average: 0.128). Heritability decreased slightly as THI increased, and began to increase at a THI of 79. The predicted bull EBV ranking varied with THI. Conclusion: We conclude that genetic evaluation using the THI function could be useful for selecting bulls for heat tolerance in South Korea.

• Asian-Australasian Journal of Animal Sciences
• /
• 제14권12호
• /
• pp.1683-1689
• /
• 2001

The levels of urea nitrogen both in blood (BUN) and milk (MUN), and milk protein (MP) reflect protein and energy intake in dairy herd feeding. Blood and milk constituents may be changes rhythmically and influence by different sampling time within a day and after feeding. Trials were conducted using five dietary treatments in both lactating and dry cows to study the effects of sampling time on concentrations of BUN, MUN and whole blood ammonia nitrogen (BAN) in practical dairy cow feeding in Taiwan. The conventional feed ingredients and forages including corn silage, alfalfa hay, timothy or pangola hay and corn grain were used as major source of the diet to follow practical dairy cow feeding. Five different diets were varying in amounts (low=L; standard=S; high=H) of crude protein (P) and energy (E) according to the NRC (1989). The energy to protein ratios in kcal/kg for the PSES, PLES, PHES, PSEH and PSEL were 10.82, 12.54, 9.41, 12.53 and 9.13 in lactating cows, and 11.38, 13.33, 9.78, 13.28 and 9.74 in dry cows, respectively. Results showed that after feeding at 9:30, BUN reached peak at 13:30 and was significantly higher than those to that sampled at 14:30 to 18:30 (p<0.05) in dry cows. Therefore the best blood sampling time for urea nitrogen assay in dry cows is 4 hours after morning feeding. In lactating cows, BUN of 13:30 was significantly higher than those of 8:30 to 11:30 (p<0.05), but there were no significant difference between the BUN values of other sampling time. Hence the suitable blood sampling time for BUN value in lactating cows was located on 3 to 8 hours after morning feeding, but the best time was 4 hours after morning feeding. MUN content is significantly higher in the afternoon collected bulk milk than the fore-strip morning milk (p<0.05), therefore the best sampling time for MUN is from afternoon collected bulk milk. Diurnal BAN changed without traceable rhythmic pattern and was negatively correlated to the BUN (r = -0.78). It is suggested that BAN may not be a good indicator for monitoring dairy cow feeding.

• 지능정보연구
• /
• 제10권3호
• /
• pp.39-57
• /
• 2004

우유생산 농가에서는 그들 젖소의 우유를 저장하는 탱크 (bulk tank milk: BTM)로부터 채취된 샘플로부터 분석된 우유에 대한 품질관련 항목들, 즉 체세포 수 (somatic cell count: SCC), 표준 plate count (standard plate count: SPC), 사전 incubation count (preliminary incubation count: PIC) 등에 관한 정보를 정기적으로 제공 받는다. 이러한 정보는 일정기간 쌓이게 되면 우유의 품질을 유지하고 목장을 관리할 수 있는 중요한 지식 베이스가 될 수 있다. 그러나 우유 품질이나 목장의 관리상태를 평가하는 기준은 모호하고 퍼지한 용어로 많이 표현되고 있다. 즉 우유 품질을 최상급, 상급, 중간, 불량으로 표시하거나 목장의 관리상태를 아주 양호, 양호, 미흡 등으로 표시한다. 이러한 서술방식은 퍼지이론에서의 모호한 상태를 표현하는 기준과 많이 부합되고 있다. 본 연구의 목적은 BTM으로부터 추출한 샘플로부터 미생물학적 분석을 통해서 나온 결과를 이용해서 BTM의 품질과 목장의 관리상태에 대하여 추론하는 것을 목표로 하고 있다. 따라서 퍼지추론엔진에 기초하여 퍼지로직 기반의 추론방법을 개발하고 실제 데이터를 이용해서 평가하였다. 입력 데이터로는 Bulk Tank SCC, SPC, PIC, laboratory pasteurization count (LPC), non agalactiae Streptococci, Streptococci like organisms, Staphylococcus aureus등이다. 이러한 입력자료에 근거하여 BTM의 품질상태를 아주 양호, 양호, cooling문제, 청결문제, 환경적 mastitis, 환경적/청결 복합문제로 분류하고, 낙농가로부터 채취한 실제 데이터를 이용하여 추론하였다. 본 퍼지 추론 결과는 낙농생산자, 컨설턴트, 수의사 등 관련 종사자들에게 의사결정을 위한 참고자료로서 활용이 가능하다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제8권5호
• /
• pp.499-503
• /
• 1995

The performance records of 410 Holstein Friesian crossbred cows belonging to seven genetic groups (Fl, 3/4, 1/4, 5/8, 3/8, triple cross and miscellaneous cross) maintained at Livestock Production Research Institute, Bahadurnagar, Okara were analyzed for various parameters of lifetime traits. For the analysis 2 data sets were made. Data set I included all the cows disposed off from the herd which have completed at least one lactation while for data set II performance traits for only first five lactations were considered. The data was analyzed by Mixed Model Least squares and Maximum Likelihood computer programme PC-I version. The least squares means ${\times}$ standard errors for data set I (periods are in days and milk yield is in litres) were $994.5{\pm}15.5$, $1,877.0{\pm}70.9$, $1,651.9{\pm}19.3$, $2,533.7{\pm}36.5$, $3,530.0{\pm}40.5$, $15,785.2{\pm}320.0$, $8.46{\pm}0.19$, $5.66{\pm}0.16$ and $3.79{\pm}0.08$, respectively for age at first calving (APC), Ist lactation milk yield (FLMY), productive life (PL), herd life (HL), total life (TL), lifetime milk yield (LTMY), milk yield per day of productive life (MY/PL), milk yield per day of herd life (MY/HL) and milk yield per day of total life (MY/TL). For data set II these values were $1,004.2{\pm}21.2$, $2,220.5{\pm}113.1$, $1,429.1{\pm}40.8$, $2,302.1{\pm}73.3$, $3,307.2{\pm}77.3$, $13,189.7{\pm}667.4$, $9.10{\pm}0.34$, $5.66{\pm}0.25$ and $4.02{\pm}0.18$ in the same order. For data set I the effect of year of first calving was significant for AFC, FLMY, PL, HL, LTMY and MY/PL. The season of Ist calving was significant only for MY/PL. The effect of genetic group was significant for AFC, FLMY, MY/PL and MY/TL while the effect of parity was significant for all the traits. For data set II the effect of year of Ist calving was significant only for AFC, FLMY and PL while the season of Ist calving was significant for FLMY and PL while the effect of genetic groups was significant for MY/HL only. The lifetime production performance is in general close to the various estimates reported in the literature.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권8호
• /
• pp.1073-1082
• /
• 2012

We first sought to clarify the effects of discounted rate, survival rate, and lactation persistency as a component trait of the selection index on net merit, defined as the first five lactation milks and herd life (HL) weighted by 1 and 0.389 (currently used in Japan), respectively, in units of genetic standard deviation. Survival rate increased the relative economic importance of later lactation traits and the first five lactation milk yields during the first 120 months from the start of the breeding scheme. In contrast, reliabilities of the estimated breeding value (EBV) in later lactation traits are lower than those of earlier lactation traits. We then sought to clarify the effects of applying single nucleotide polymorphism (SNP) on net merit to improve the reliability of EBV of later lactation traits to maximize their increased economic importance due to increase in survival rate. Net merit, selection accuracy, and HL increased by adding lactation persistency to the selection index whose component traits were only milk yields. Lactation persistency of the second and (especially) third parities contributed to increasing HL while maintaining the first five lactation milk yields compared with the selection index whose only component traits were milk yields. A selection index comprising the first three lactation milk yields and persistency accounted for 99.4% of net merit derived from a selection index whose components were identical to those for net merit. We consider that the selection index comprising the first three lactation milk yields and persistency is a practical method for increasing lifetime milk yield in the absence of data regarding HL. Applying SNP to the second- and third-lactation traits and HL increased net merit and HL by maximizing the increased economic importance of later lactation traits, reducing the effect of first-lactation milk yield on HL (genetic correlation ($r_G$) = -0.006), and by augmenting the effects of the second- and third-lactation milk yields on HL ($r_G$ = 0.118 and 0.257, respectively).