• 제목/요약/키워드: Age at first calving

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Genetic Evaluation of First Lactation Traits in Sahiwal Cattle Using Restricted Maximum Likelihood Technique

  • Choudhary, V.;Kothekar, M.D.;Raheja, K.L.;Kasturiwale, N.N.;Khire, D.W.;Kumar, P.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권5호
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    • pp.639-643
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    • 2003
  • The data on 283 Sahiwal cows, sired by 16 bulls, maintained at Cattle Breeding Farm of Nagpur Veterinary College and Dairy Farm of Agricultural College, Nagpur, were considered for the estimation of genetic parameters. Variance and covariance estimates of first lactation traits were obtained using restricted maximum likelihood technique (REML). When first lactation milk yield (FLMY), first lactation length (FLL) and average daily yield (ADY) traits were considered for REML analysis, the heritabilities were $0.184{\pm}0.146$, $0.132{\pm}0.131$ and $0.141{\pm}0.133$, respectively. While, genetic and phenotypic correlations between them were medium to high except phenotypic correlations between FLL and ADY (-0.025). REML procedure considering FLMY, age at first calving (AFC) and first service period (FSP) combination exhibits heritabilities as $0.274{\pm}0.173$, $0.506{\pm}0.233$ and $0.274{\pm}0.172$, respectively. Genetic correlations were $-0.120{\pm}0.376$, $0.225{\pm}0.423$ and $0.365{\pm}0.331$ between FLMY and AFC, FLMY and FSP, AFC and FSP, respectively. Phenotypic correlations were 0.057, 0.289 and 0.123, respectively. Considering all five traits REML combination heritabilities estimated were $0.238{\pm}0.162$, $0.160{\pm}0.139$, $0.136{\pm}0.132$, $0.409{\pm}0.209$ and $0.259{\pm}0.168$ for FLMY, FLL, ADY, AFC and FSP, respectively. The genetic correlations were positive except FLMY and AFC. The phenotypic correlations were also positive except FLL and ADY, ADY and FSP. Almost all estimates were associated with high standard error.

PRODUCTION PERFORMANCE AND MILK PRODUCING EFFICIENCY IN DIFFERENT FILIAL GROUPS OF H. FRIESIAN × SAHIWAL HALFBREDS

  • Chaudhry, M.Z.;Tahir, M.J.;Rafique, M.
    • Asian-Australasian Journal of Animal Sciences
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    • 제7권3호
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    • pp.383-387
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    • 1994
  • Six heifers each of $F_1$, $F_2$, $F_3$, $F_4$ H. Friesian $\times$ Sahjwal halfbreds and pure Sahiwal with overall average initial age and live weight of $315.6{\pm}134.8 days$ and $143.8{\pm}48.5kg$, respectively were used for this study. The under trial animals were fed according to N.R.C. (1978). The overall average age at maturity, first conception and first calving was $563.8{\pm}116.8$, $675.8{\pm}135.6$ and $956.8{\pm}149.8days$ with live weights as $302.2{\pm}58.6$, $342.6{\pm}41.5$ and $433.9{\pm}38.1kg$, respectively. The overall 305 days and total milk yield for 1st lactation was $2,729.0{\pm}669.3$ and $2,992.7{\pm}377.5litre$ while the FCM (at 4%) was $2,934.2{\pm}410.8litre$. The lactation length was $336.6{\pm}69.6days$. The fat and solids not fat contents were $4.5{\pm}0.2$ and $8.2{\pm}0.3percent$, respectively. The milk production in Sahiwal cows was significantly lower than crossbred cows. The services per conception were $2.5{\pm}1.3$. The overall per head per day consumption of DM, TCP and ME was $10.9{\pm}1.2kg$, $1,399{\pm}199gm$ and $22.6{\pm}2.4 M.Cal.$, respectively. The overall milk producing efficiency for the production of one litre of FCM was $1.12{\pm}0.15kg$ of DM, $142.2{\pm}17.76gm$ of TCP and $2.31{\pm}0.27M.Cal.$ of energy while the feeding cost was Rs. $1.46{\pm}0.22$ per litre of FCM produced. The feeding cost per litre FCM was significantly higher in Sahiwal and $F_2$ than in other genetic groups.

Estimation of Genetic Parameters for Somatic Cell Scores of Holsteins Using Multi-trait Lactation Models in Korea

  • Alam, M.;Cho, C.I.;Choi, T.J.;Park, B.;Choi, J.G.;Choy, Y.H.;Lee, S.S.;Cho, K.H.
    • Asian-Australasian Journal of Animal Sciences
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    • 제28권3호
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    • pp.303-310
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    • 2015
  • The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

Genetic study of quantitative traits supports the use of Guzera as dual-purpose cattle

  • Carrara, Eula Regina;Peixoto, Maria Gabriela Campolina Diniz;Veroneze, Renata;Silva, Fabyano Fonseca e;Ramos, Pedro Vital Brasil;Bruneli, Frank Angelo Tomita;Zadra, Lenira El Faro;Ventura, Henrique Torres;Josahkian, Luiz Antonio;Lopes, Paulo Savio
    • Animal Bioscience
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    • 제35권7호
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    • pp.955-963
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    • 2022
  • Objective: The aim of this study was to estimate genetic parameters for 305-day cumulative milk yield and components, growth, and reproductive traits in Guzerá cattle. Methods: The evaluated traits were 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), protein (PY305), lactose (LY305), and total solids (SY305); age at first calving (AFC) in days; adjusted scrotal perimeter (cm) at the ages of 365 (SP365) and 450 (SP450) days; and adjusted body weight (kg) at the ages of 210 (W210), 365 (W365), and 450 (W450) days. The (co)variance components were estimated using the restricted maximum likelihood method for single-trait, bi-trait and tri-trait analyses. Contemporary groups and additive genetic effects were included in the general mixed model. Maternal genetic and permanent environmental effects were also included for W210. Results: The direct heritability estimates ranged from 0.16 (W210) to 0.32 (MY305). The maternal heritability estimate for W210 was 0.03. Genetic correlation estimates among milk production traits and growth traits ranged from 0.92 to 0.99 and from 0.92 to 0.99, respectively. For milk production and growth traits, the genetic correlations ranged from 0.33 to 0.56. The genetic correlations among AFC and all other traits were negative (-0.43 to -0.27). Scrotal perimeter traits and body weights showed genetic correlations ranging from 0.41 to 0.46, and scrotal perimeter and milk production traits showed genetic correlations ranging from 0.11 to 0.30. The phenotypic correlations were similar in direction (same sign) and lower than the corresponding genetic correlations. Conclusion: These results suggest the viability and potential of joint selection for dairy and beef traits in Guzerá cattle, taking into account reproductive traits.

뉴질랜드 (Palmerston North) 의 낙농 현황과 번식 및 번식장해에 관한 연구 (II) Palmerston North 지역의 낙농 번식현 황과 번식장해에 관한 조사 (Studies on Dairy Farming Status, Reproductive Efficiencies and Disorders in New Zealand (II) A Survey on Reproductive Efficiencies and Disorders in Palmerston North Area)

  • 김중계;맥도날드
    • 한국가축번식학회지
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    • 제24권1호
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    • pp.19-33
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    • 2000
  • New Zealand, Palmerston North 지역의 낙농가 80여 개 낙농가에 1998년 2월부터 1998년 7월까지 우편설문지에 의해 조사되었다. 주어진 질문항목은 1) General characteristics, 2) Milk yield 와 feed supplementary, 3) Reproductive efficiencies(14개 질의), 4) Reproductive disorders (12개 질의) 4개 항목을 포함하는 합계 43개의 질문을 내포하고 있었다. 낙농가의 웅답자 38농가 (47.5%)에서 회수된 질의문 4개 항목 중 3), 4) 항목에 해당되는 번식능력 향상을 위한 번식상황, 번식장해, 젖소의 일반적인 질환(대사질환 포함) 및 도태 등에 관한 조사결과를 집계분석하여 우리나라 낙농인 (특히 제주도)들에게 인식시키고, New Zealand 성적과 비교하였던 바 그 결과를 요약하면 다음과 같다. 1. Palmers ton North 지역에서 인공수정만을 실행하고 있는 낙농가는 38농가 중 15농가 (39.5%)뿐이고 나머지 23농가(60.5%)는 임신율을 향상시키기 위하여 대부분 약 5∼6 마리의 종모우를 확보하고 있었다. 대부분의 농가는 대략 10월 20일경에서 12월 10일 까지 약 42일간 인공수정을 실시하고 그 후부터 익년 1월 19일까지 (약 42일) 종모우로 자연교미를 시도하고 있었다. 인공수정 개시 후 전체 종빈우 중 3주 동안에 발정 발현율이 84.7%, 6주에는 93.9%, 그리고 10주까지 약 97.9%의 발정두수가 포착되여 임신으로 유도되었다. 2. 미경산우의 첫발정 1월령, 첫수정 l월령 그리고 첫분만 1월령은 각각 대략 11.0, 15.4 과 24.7개월이었고, 임신까지의 수정회수는 약 1.4회였다. 또한 분만 후 발정재귀와 첫수정일은 각각 38,68일로 상당히 우리나라보다 빠른 성적을 보여주고 있었다. 3. 전체 수정두수에 있어서 송아지 분만율은 90.9%이고, 유산된 암소 1.6% 이었으며, 공태율은 7.4% 이었고, 사육규모두수가 증가됨으로써 분만율은 떨어졌으며, 공태율도 약간씩 낮아지는 경향을 보여 주었다. 4. 번식장해에 있어서 사산, 후산정체 그리고 분만장해는 각각 평균 5.3, 3.7, 5.5%로서 사육 규모에 따라서 차이를 볼 수 없었다. 5. 대사질병중 유열, 신경성강직, 케토시스 발생율은 각각 평균 3.6, 3.0, 1.0%로 사육규모 두수별 큰 차이가 없었다. 그리고 치료 대상 중에서 분만장해는 평균 3.1%, 유방염 발생은 6.7%로 높았으나, 사육규모가 커질수록 비율이 떨어지는 경향을 보여주었으며, 다리절음은 평균 8.6%로서 400두 이상 사육규모에서 10.1% 높은 경향을 나타내었다. 6. 낙농가에서 사육 중 도태두수는 평균 15.5%서 연령, 다리절음, 기타 질병에 따른 도태두수는 각각 평균 2.9, 1.8, 4.3%로 사유규모별 차이가 없었으나, 저우유생산량, 번식장해의 의한 도태두수는 각각 평균 4.3, 5.1%로 사육두수가 많아짐에 따라서 낮아지는 경향을 보여 주었다. 7. 우리나라에서 조사된 성적과 비교할 때 대체로 일반적인 번식효율과 분만장해는 양호하였으나, 발절음, 대사질환, 그리고 도태율 동은 New Zealand 에서 높은 수치를 보여 주었다.

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Estimation of genetic parameters of the productive and reproductive traits in Ethiopian Holstein using multi-trait models

  • Ayalew, Wondossen;Aliy, Mohammed;Negussie, Enyew
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권11호
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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.

Physiochemical characteristics and fermentation ability of milk from Czech Fleckvieh cows are related to genetic polymorphisms of β-casein, κ-casein, and β-lactoglobulin

  • Kyselova, Jitka;Jecminkova, Katerina;Matejickova, Jitka;Hanus, Oto;Kott, Tomas;Stipkova, Miloslava;Krejcova, Michaela
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권1호
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    • pp.14-22
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    • 2019
  • Objective: The aim of the study was to find a possible association between the ${\beta}-$ and ${\kappa}-casein$ and ${\beta}-lactoglobulin$ genotypes and important milk physiochemical and technological characteristics such as acidity, alcohol stability, the contents of some minerals and the parameters of acid fermentation ability (FEA) in Czech Fleckvieh Cattle. Methods: Milk and blood samples were collected from 338 primiparous Czech Fleckvieh cows at the same stage of lactation. The genotypes of individual cows for ${\kappa}-casein$ (alleles A, B, and E) and ${\beta}-lactoglobulin$ (alleles A and B) were ascertained by polymerase chain reaction-restriction fragment length polymorphism, while their ${\beta}-casein$ (alleles $A^1$, $A^2$, $A^3$, and B) genotype was determined using melting curve genotyping analysis. The data collected were i) milk traits including active acidity (pH), titratable acidity (TA), alcohol stability (AS); calcium (Ca), phosphorus (P), sodium (Na), magnesium (Mg), and potassium (K) contents; and ii) yoghurt traits including active acidity (Y-pH), titratable acidity (Y-TA), and the counts of both Lactobacilli and Streptococci in 1 mL of yoghurt. A linear model was assumed with fixed effects of herd, year, and season of calving, an effect of the age of the cow at first calving and effects of the casein and lactoglobulin genotypes of ${\beta}-CN$ (${\beta}-casein$, CSN2), ${\kappa}-CN$ (${\kappa}-casein$, CSN3), and ${\beta}-LG$ (${\beta}-lactoglobulin$, LGB), or the three-way interaction between those genes. Results: The genetic polymorphisms were related to the milk TA, AS, content of P and Ca, Y-pH and Lactobacilli number in the fresh yoghurt. The CSN3 genotype was significantly associated with milk AS (p<0.05). The effect of the composite CSN2-CSN3-LGB genotype on the investigated traits mostly reflected the effects of the individual genes. It significantly influenced TA (p<0.01), Y-pH (p<0.05) and the log of the Lactobacilli count (p<0.05). Conclusion: Our findings indicate that the yoghurt fermentation test together with milk proteins genotyping could contribute to milk quality control and highlight new perspectives in dairy cattle selection.

Factors Influencing Genetic Change for Milk Yield within Farms in Central Thailand

  • Sarakul, M.;Koonawootrittriron, S.;Elzo, M.A.;Suwanasopee, T.
    • Asian-Australasian Journal of Animal Sciences
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    • 제24권8호
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    • pp.1031-1040
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    • 2011
  • The objective of this study was to characterize factors influencing genetic improvement of dairy cattle for milk production at farm level. Data were accumulated from 305-day milk yields and pedigree information from 1,921 first-lactation dairy cows that calved from 1990 to 2007 on 161 farms in Central Thailand. Variance components were estimated using average information restricted maximum likelihood procedures. Animal breeding values were predicted by an animal model that contained herd-year-season, calving age, and regression additive genetic group as fixed effects, and cow and residual as random effects. Estimated breeding values from cows that calved in a particular month were used to estimate genetic trends for each individual farm. Within-farm genetic trends (b, regression coefficient of farm milk production per month) were used to classify farms into 3 groups: i) farms with negative genetic trend (b<-0.5 kg/mo), ii) farms with no genetic trend (-0.5 kg/$mo{\leq}b{\leq}0.5$ kg/mo), and iii) farms with positive genetic trend (b>0.5 kg/mo). Questionnaires were used to gather information from individual farmers on educational background, herd characteristics, farm management, decision making practices, and opinion on dairy farming. Farmer's responses to the questionnaire were used to test the association between these factors and farm groups using Fisher's exact test. Estimated genetic trend for the complete population was $0.29{\pm}1.02$ kg/year for cows. At farm level, most farms (40%) had positive genetic trend ($0.63{\pm}4.67$ to $230.79{\pm}166.63$ kg/mo) followed by farms with negative genetic trend (35%; $-173.68{\pm}39.63$ to $-0.62{\pm}2.57$ kg/mo) and those with no genetic trend (25%; $-0.52{\pm}3.52$ to $0.55{\pm}2.68$ kg/mo). Except for educational background (p<0.05), all other factors were not significantly associated with farm group.

Accuracy of genomic-polygenic estimated breeding value for milk yield and fat yield in the Thai multibreed dairy population with five single nucleotide polymorphism sets

  • Wongpom, Bodin;Koonawootrittriron, Skorn;Elzo, Mauricio A.;Suwanasopee, Thanathip;Jattawa, Danai
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권9호
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    • pp.1340-1348
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    • 2019
  • Objective: The objectives were to compare variance components, genetic parameters, prediction accuracies, and genomic-polygenic estimated breeding value (EBV) rankings for milk yield (MY) and fat yield (FY) in the Thai multibreed dairy population using five single nucleotide polymorphism (SNP) sets from GeneSeek GGP80K chip. Methods: The dataset contained monthly MY and FY of 8,361 first-lactation cows from 810 farms. Variance components, genetic parameters, and EBV for five SNP sets from the GeneSeek GGP80K chip were obtained using a 2-trait single-step average-information restricted maximum likelihood procedure. The SNP sets were the complete SNP set (all available SNP; SNP100), top 75% set (SNP75), top 50% set (SNP50), top 25% set (SNP25), and top 5% set (SNP5). The 2-trait models included herd-year-season, heterozygosity and age at first calving as fixed effects, and animal additive genetic and residual as random effects. Results: The estimates of additive genetic variances for MY and FY from SNP subsets were mostly higher than those of the complete set. The SNP25 MY and FY heritability estimates (0.276 and 0.183) were higher than those from SNP75 (0.265 and 0.168), SNP50 (0.275 and 0.179), SNP5 (0.231 and 0.169), and SNP100 (0.251and 0.159). The SNP25 EBV accuracies for MY and FY (39.76% and 33.82%) were higher than for SNP75 (35.01% and 32.60%), SNP50 (39.64% and 33.38%), SNP5 (38.61% and 29.70%), and SNP100 (34.43% and 31.61%). All rank correlations between SNP100 and SNP subsets were above 0.98 for both traits, except for SNP100 and SNP5 (0.93 for MY; 0.92 for FY). Conclusion: The high SNP25 estimates of genetic variances, heritabilities, EBV accuracies, and rank correlations between SNP100 and SNP25 for MY and FY indicated that genotyping animals with SNP25 dedicated chip would be a suitable to maintain genotyping costs low while speeding up genetic progress for MY and FY in the Thai dairy population.