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1.
This study was aimed to assess genetic parameters for 13 traits in heifers and first-parity Holstein dairy cows. Data consisted of calving and insemination dates of 14,707 Holstein dairy cows in Isfahan province of Iran. Reproductive traits included age at first service (AFS), first service to conception (FSTC), gestation length (GL), age at first calving (AFC), calving to first service (CTFS), days open (DO), calving interval (CI), number of services per conception (NS), and non-return rate at 56 days (NRR). Model equations were optimized using GLM procedure in SAS package following genetic analysis using animal models in ASREML software. Minimum and maximum departure from normal distribution for phenotypic records belonged to AFS, NRR, GL, DO, CI and AFC, NS, FSTC, CTFS, respectively. Estimated heritability varied from 0.002 (NRR) to 0.184 (GL) in heifers and from 0.003 (NRR) to 0.153 (GL) in first-parity cows. AFS, CTFS, and GL were noticeably heritable compared to other assessed traits. Estimated absolute additive genetic correlations were in the range of 0.01 (NRR and AFS) and 0.99 (NRR and NS) in heifers and 0.07 (GL and CI) to 1 (FSTC and CI) in cows. Additive genetic correlations were antagonistic between AFS and other traits, except AFC. Interestingly, NRR which has been included in sire catalogs had the highest average absolute genetic associations with other traits.  相似文献   

2.
Fertility health disorders from the early lactation period including retained placenta (REPLA), metritis (MET), corpus luteum persistence (CLP), anoestria/acyclia (AOEAC) and ovarial cysts (OC), as well as overall disease categories (disorders during the postpartal period (DPP), ovary infertility (OINF), overall trait definition “fertility disorders” (FD)), were used to estimate genetic (co)variance components with female fertility and test‐day traits. The disease data set comprised 25,142 Holstein cows from parities 1, 2 and 3 resulting in 43,584 lactations. For disease traits, we used the binary trait definition (sick or healthy) and disease count data reflecting the sum of treatments for the same disease within lactation or within lactation periods. Statistical modelling included single and multiple trait repeatability animal models for all trait combinations within a Bayesian framework. Heritabilities for binary disease traits ranged from 0.04 (OC) to 0.10 (REPLA) and were slightly lower for the corresponding sum trait definitions. Correlations between both trait definitions were almost one, for genetic as well as for permanent environmental effects. Moderate to high genetic correlations were found among puerperal disorders DPP, REPLA and MET (0.45–0.98) and among the ovarian disorders OINF, AOEAC, CLP and OC (0.59–0.99). Genetic correlations between puerperal and ovarian disorders were close to zero, apart from the REPLA–OC association (0.55). With regard to fertility disorders and productivity in early lactation, a pronounced genetic antagonistic relationship was only identified between OC and protein yield. Genetic correlations between fertility disorders and test‐day SCS were close to zero. OINF and all diseases contributing to OINF were strongly correlated with the female fertility traits “interval from calving to first service,” “interval from service to pregnancy” and “interval from calving to pregnancy.” The strong correlations imply that fertility disorders could be included in genetic evaluations of economic fertility traits as correlated predictors. Vice versa, a breeding focus on female fertility traits will reduce genetic susceptibility to OC, CLP and AOEAC.  相似文献   

3.
宁夏地区荷斯坦牛青年牛繁殖性状遗传参数估计   总被引：4，自引：3，他引：1  
旨在探究青年牛繁殖性状遗传能力群体遗传参数,评估不同配种季节间青年牛繁殖性状基因型与环境的互作效应(G×E).本研究利用宁夏地区12个牧场2007-2019年荷斯坦牛繁殖事件信息记录,计算青年牛繁殖性状包括:首配日龄(AFS)、初产日龄(AFC)、首次配种后56天不返情率(NRR56)、首末次配种间隔(IFL)、妊娠期...  相似文献   

4.
Genetic correlations between body condition score (BCS) and fertility traits in dairy cattle were estimated using bivariate random regression models. BCS was recorded by the Swiss Holstein Association on 22,075 lactating heifers (primiparous cows) from 856 sires. Fertility data during first lactation were extracted for 40,736 cows. The fertility traits were days to first service (DFS), days between first and last insemination (DFLI), calving interval (CI), number of services per conception (NSPC) and conception rate to first insemination (CRFI). A bivariate model was used to estimate genetic correlations between BCS as a longitudinal trait by random regression components, and daughter's fertility at the sire level as a single lactation measurement. Heritability of BCS was 0.17, and heritabilities for fertility traits were low (0.01-0.08). Genetic correlations between BCS and fertility over the lactation varied from: -0.45 to -0.14 for DFS; -0.75 to 0.03 for DFLI; from -0.59 to -0.02 for CI; from -0.47 to 0.33 for NSPC and from 0.08 to 0.82 for CRFI. These results show (genetic) interactions between fat reserves and reproduction along the lactation trajectory of modern dairy cows, which can be useful in genetic selection as well as in management. Maximum genetic gain in fertility from indirect selection on BCS should be based on measurements taken in mid lactation when the genetic variance for BCS is largest, and the genetic correlations between BCS and fertility is strongest.  相似文献   

5.
The test‐day milk fat‐to‐protein ratio (TD‐FPR) could serve as a measure of energy balance status and might be used as a criterion to improve metabolic stability and fertility through genetic selection. Therefore, genetic parameters for fertility traits, test‐day milk yield (TD‐MY) and TD‐FPR, as well as, their relationships during different stages of lactation, were estimated on data collected from 25 968 primiparous Thai dairy crossbred cows. Gibbs sampling algorithms were implemented to obtain (co)variance components using both univariate linear and threshold animal models and bivariate linear‐linear and linear‐threshold animal models with random regression. Average TD‐MY and TD‐FPR were 12.60 and 1.15. Heritability estimates for TD‐MY, TD‐FPR and selected fertility traits ranged from 0.31 to 0.58, 0.17 to 0.19 and 0.02 to 0.05, respectively. Genetic correlations among TD‐FPR and TD‐MY, TD‐FPR and fertility traits, and TD‐MY and fertility traits ranged from 0.05 to ‐0.44, from ‐0.98 to 0.98 and ‐0.22 to 0.79, respectively. Selection for lower TD‐FPR would decrease numbers of inseminations per conception and increase conception at first service and pregnancy within 90 days. In addition, cow selection based only on high milk production has strong effects to prolong days to first service, days open and calving interval.  相似文献   

6.
Relationships between herd fertility measurements and financial loss from reproductive failure in dairy herds were studied. Financial losses attributable to prolonged calving interval and forced replacement from reproductive failure were considered. Herd fertility parameters were calculated from artificial insemination and calving data (i.e. calving to first service interval, non-return rate 56 days after first service, percentage of correct inseminations carried out in the interval 18–24 days, fertility status, calving interval, an oestrus index and number of insemination per average cow present in the herd.

The herd fertility parameters were moderately-highly related to loss due to suboptimal calving interval (r=0.20−0.79 in absolute values), but only slightly related to losses due to forced replacement (r<0.17 in absolute values).

Repeatabilities, calculated over a 3-year period, were high for the interval to first service, non-return rate and the oestrus index (0.52−0.67) and moderate for percentage correct reinseminations, fertility status, calving interval and loss due to suboptimal calving interval (0.38−0.48). Repeatability of loss due to forced replacement was low (0.20).

In a regression analysis no herd fertility parameter was fitted with respect to loss from forced replacement. Loss due to suboptimal calving interval at herd level was best estimated by the oestrus index (R2=0.63), the addition of the interval to first service to the regression equation explained a further 10% of the variation between herds. It is suggested that the oestrus index and the interval to first service should be presented as management aids to monitor herd fertility.  相似文献   


7.
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8.
Data comprising 7211 lactation records of 2894 cows were used to estimate genetic and phenotypic parameters for milk production (lactation milk yield, LMY and lactation length, LL) and fertility (calving interval, CI; number of services per conception, NSC and age at first calving, AFC) traits. Genetic, environmental and phenotypic trends were also estimated. Variance components were estimated using univariate, bivariate and trivariate animal models on based restricted maximum likelihood procedures. Univariate models were used for each trait, while bivariate models were used to estimate genetic and phenotypic correlations between milk production and fertility traits and between LMY, LL, CI and NSC within each lactation. Trivariate models were used in the analysis of LMY, LL, CI and NSC in the first three lactations. Heritability estimates from the univariate model were 0.16, 0.07, 0.03, 0.04 and 0.01 for LMY, LL, CI, AFC and NSC, respectively. The heritability estimates from trivariate analysis were higher for milk production traits than those from univariate analyses. Genetic correlations were high and undesirable between milk production and fertility traits, while phenotypic correlations were correspondingly low. Genetic trends were close to zero for all traits, while environmental and phenotypic trends fluctuated over the study period.  相似文献   

9.
Data were evaluated from a purebred Holstein herd (n = 1274) kept near Khartoum, a hot and dry area, from 1990 to 1996. The mixed model procedure in SAS was used to analyse the reproductive traits. The mean gestation length, days dry, number of services per conception, days from calving to first oestrus, days from calving to conception, calving interval and breeding efficiency were 279 days, 104 days, 4.2, 85.8 days, 208.9 days, 486.2 days and 74.9%, respectively. Factors that had significant effects (p<0.01) on all the reproductive measures under study were the year and month of calving, and parity.The heritability estimates for all traits under investigation were zero. The repeatability estimates for the numbers of services per conception, days from calving to conception, days from calving to first oestrus and calving interval were 0.21±0.021, 0.12±0.024, 0.03±0.018 and 0.00, respectively. The phenotypic correlation for calving interval with numbers of service per conception was 0.05, that with days from calving to first oestrus was 0.06 and that with days from calving to conception was 0.07. Other correlations ranged from 0.00 to 0.28. The simple correlation coefficients between production and reproductive measures ranged from –0.06 to 0.45.  相似文献   

10.
Estimates of covariance components between scrotal circumference, serving capacity, days to calving, and yearling and final weight were obtained for Hereford, Angus, and Zebu cross cattle in temperate and tropical Australia. Analyses were carried out by REML employing a derivative-free algorithm and fitting bivariate animal models. Aspects of modeling and computational requirements related to the use of this method are discussed. Estimates of heritabilities agreed closely with those from univariate analyses, being low for female reproductive performance and moderate to high for male reproduction and growth. Estimates of genetic correlation between male and female fertility traits were low but favorable, being -.25, -.28, and -.41 between scrotal circumference and days to calving for Herefords, Angus, and Zebu crosses, respectively. Genetic correlations between male reproductive traits and weights ranged from .24 to .52 for the temperate breeds and were higher (.65 to .69) for Zebu crosses. Phenotypic correlations between scrotal circumference and weights were similar for all breeds, ranging from .32 to .47, whereas serving capacity and weights were phenotypically unrelated. Estimates of correlations between days to calving and weights were less consistent. Phenotypically, there was little association between the two traits. Genetic correlations for Zebu crosses were negative and low to moderate (-.36 to -.66) and estimates for Angus were close to zero.  相似文献   

11.
Calving records (n = 6,763) obtained from first, second, and third parities of 3,442 spring-calving, Uruguayan Aberdeen Angus cows were used to estimate heritabilities and genetic correlations for the linear trait calving day (CD) and the binary trait calving success (CS), using models that considered CD and CS at 3 calving opportunities as separate traits. Three approaches were defined to handle the CD observations on animals that failed to calve: 1) the cows were assigned a penalty value of 21 d beyond the last observed CD record within contemporary group (PEN); 2) the censored CD values were randomly obtained from a truncated normal distribution (CEN); and 3) the CD records were treated as missing, and the parameters were estimated in a joint threshold-linear analysis including CS traits (TLMISS). The models included the effects of contemporary group (herd x year of calving x mating management), age at calving (3 levels), physiological status at mating (nonlactating or lactating), animal additive genetic effects, and residual. Estimates of heritability for CD traits in the PEN and CEN data sets ranged from 0.20 to 0.31, with greater values in the first calving opportunity. Genetic correlations were positive and medium to high in magnitude, 0.57 to 0.59 in the PEN data set and 0.38 to 0.91 in the CEN data set. In the TLMISS data set, heritabilities ranged from 0.19 to 0.23 for CD and 0.37 to 0.42 for CS. Genetic correlations between CD traits varied between 0.82 and 0.88; between CS traits, genetic correlations varied between 0.56 and 0.80. Negative (genetically favorable), medium to high genetic correlations (-0.54 to -0.91) were estimated between CD and CS traits, suggesting that CD could be used as an indicator trait for CS. Data recording must improve in quality for practical applications in genetic evaluation for fertility traits.  相似文献   

12.
Single nucleotide polymorphism (SNP) data enable the estimation of inbreeding at the genome level. In this study, we estimated inbreeding levels for 19,075 Finnish Ayrshire cows genotyped with a low‐density SNP panel (8K). The genotypes were imputed to 50K density, and after quality control, 39,144 SNPs remained for the analysis. Inbreeding coefficients were estimated for each animal based on the percentage of homozygous SNPs (FPH), runs of homozygosity (FROH) and pedigree (FPED). Phenotypic records were available for 13,712 animals including non‐return rate (NRR), number of inseminations (AIS) and interval from first to last insemination (IFL) for heifers and up to three parities for cows, as well as interval from calving to first insemination (ICF) for cows. Average FPED was 0.02, FROH 0.06 and FPH 0.63. A correlation of 0.71 was found between FPED and FROH, 0.66 between FPED and FPH and 0.94 between FROH and FPH. Pedigree‐based inbreeding coefficients did not show inbreeding depression in any of the traits. However, when FROH or FPH was used as a covariate, significant inbreeding depression was observed; a 10% increase in FROH was associated with 5 days longer IFL0 and IFL1, 2 weeks longer IFL3 and 3 days longer ICF2 compared to non‐inbred cows.  相似文献   

13.
The objective of this study was to evaluate the influence of inbreeding depression on traits of buffaloes from Brazil. Specifically, the traits studied were body weight at 205 and 365 days of age, average daily gain from birth to 205 days (ADG_205), average daily gain between 205 and 365 days (ADG205_365) in Mediterranean buffaloes, and milk yield, lactation length, age of first calving and calving intervals in Murrah buffaloes. Inbreeding effects on the traits were determined by fitting four regression models (linear, quadratic, exponential and Michaelis‐Menten) about the errors generated by the animal model. The linear model was only significant (P < 0.05) for growth traits (exception of ADG205_365). The exponential and Michaelis‐Menten models were significant (P < 0.01) for all the studied traits while the quadratic model was not significant (P > 0.05) for any of the traits. Weight at 205 and 365 days of age decreased 0.25 kg and 0.39 kg per 1% of increase in inbreeding, respectively. The inbred animals (F = 0.25) produced less milk than non‐inbred individuals: 50.4 kg of milk. Moreover, calving interval increased 0.164 days per 1% of increase in inbreeding. Interestingly, inbreeding had a positive effect on age at first calving and lactation length, decreasing age of first calving and increasing lactation length.  相似文献   

14.
Investigations by Robinson [Robinson, D.L., 2007. Days to calving in artificially inseminated cattle: comparison of potential traits. Livestock Science 110, 174–180] concluded that the most useful trait for assessing fertility of artificially inseminated (AI) beef cows is AI days to calving (AIDC), a trait that mimics days to calving for naturally mated cows. Various fixed and random effects were fitted to AIDC to determine the best way of modelling lactation status of the cow, the effect of service sire, using smaller contemporary groups and lowering the penalty value for non-calvers. Fitting the time interval between calving and the start of mating either as a 10-level factor or a cubic spline function explained considerably more variation than fitting the standard 2-level factor (wet or dry). Estimated permanent environmental effects of the cow were considerably reduced. This suggests that, if a cow calves late in the season (less than 60 days before she is inseminated), her fertility is reduced. Models should therefore account for this effect. If fitted, service sire explained 1.6% of phenotypic variation, compared to a much larger sire × contemporary group interaction (3% of phenotypic variation). It is therefore important to account for sire × contemporary group interactions. When the fertility of service sires is not being evaluated, service sires could be incorporated into the definition of contemporary groups. Ideally, breeders should be encouraged to formally record contemporary (or mating) groups. Reducing the size of contemporary groups (inferred from the data) by limiting the time interval between first and last inseminations from 120 to 60 days had only a marginal effect as did reducing the penalty for non-calvers from 21 to 10 days.  相似文献   

15.
Associations between types of lameness and fertility   总被引：6，自引：0，他引：6  
Four hundred and twenty-seven cases of first-reported foot lameness were recorded in 17 dairy herds in Somerset during the winter housing period. Lameness was classified into three categories: sole ulceration, digital disease (white line abscess, foreign bodies in the sole and pricked or punctured sole), and interdigital disease (lesions of the skin between claws and heel including foul in the foot, interdigital fibroma and dermatitis). In addition, a 'clinical effect score' was calculated to take account of the severity of lameness, the structures involved and the time for which the cows were clinically affected. The fertility records of lame cows were compared with those of the healthy cows nearest in parity and stage of lactation. In the lame cows the interval from calving to first service was four days longer, and the interval from calving to conception was 14 days longer than in the control cows, the pregnancy rate to first service was 46 per cent (controls 56 per cent), 2.14 services were required per conception (controls 1.72) and 16 per cent of lame cows were culled (controls 5 per cent). Lameness, first reported in the period 36 to 70 days after calving, was associated with a significant (P less than 0.01) increase in the interval from calving to first service of eight days; and sole ulceration, in the period 71 to 120 days after calving, was associated with an increase of 11 days (P less than 0.05). Lameness in all periods up to 120 days after calving was associated with significantly increased intervals from calving to conception (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
Reproductive efficiency is major determinant of the dairy herd profitability. Thus, reproductive traits have been widely used as selection objectives in the current dairy cattle breeding programs. We aimed to evaluate strategies to model days open (DO), calving interval (CI) and daughter pregnancy rate (DPR) in Brazilian Holstein cattle. These reproductive traits were analysed by the autoregressive (AR) model and compared with classical repeatability (REP) model using 127,280, 173,092 and 127,280 phenotypic records, respectively. The first three calving orders of cows from 1,469 Holstein herds were used here. The AR model reported lower values for Akaike Information Criteria and Mean Square Errors, as well as larger model probabilities, for all evaluated traits. Similarly, larger additive genetic and lower residual variances were estimated from AR model. Heritability and repeatability estimates were similar for both models. Heritabilities for DO, CI and DPR were 0.04, 0.07 and 0.04; and 0.05, 0.06 and 0.04 for AR and REP models, respectively. Individual EBV reliabilities estimated from AR for DO, CI and DPR were, in average, 0.29, 0.30 and 0.29 units higher than those obtained from REP model. Rank correlation between EBVs obtained from AR and REP models considering the top 10 bulls ranged from 0.72 to 0.76; and increased from 0.98 to 0.99 for the top 100 bulls. The percentage of coincidence between selected bulls from both methods increased over the number of bulls included in the top groups. Overall, the results of model-fitting criteria, genetic parameters estimates and EBV predictions were favourable to the AR model, indicating that it may be applied for genetic evaluation of longitudinal reproductive traits in Brazilian Holstein cattle.  相似文献   

17.
The association between lameness and fertility in dairy cows   总被引：1，自引：0，他引：1  
One thousand, four hundred and ninety-one lactations in 770 Friesian, Holstein and Ayrshire crossbred cows have been used to study the associations between lameness and fertility. Lameness was associated with a longer interval between calving and first service and a longer interval between calving and conception. The largest increases in these intervals, of 17 and 30 days, respectively, occurred in cows with either sole or white line lesions occurring between 36 and 70 days after calving. The conception rate during the 63 days before a diagnosis of lameness was made was lower (31 per cent) than at other times (40 per cent).  相似文献   

18.

The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was included as a variate in all of the analyses. Correlations between the herd-year effects indicated that factors of herd-year level conducive to increased production had a tendency to increase the number of inseminations as well as the number of reproductive treatments, although there was an earlier start and termination of the insemination period. Genetic correlations between fertility traits and production were in the range of 0.2-0.4, all of them unfavourable and higher at later parities. The genetic correlations between fertility traits in the heifer period and the same traits in first lactation were 0.7. Genetic correlations between the first and second lactation varied between 0.7 and 0.9, and between the second and third lactation they were all 0.9 or higher. In conclusion, fertility and production traits need to be selected for simultaneously if fertility is going to be maintained along further genetic improvement on production, and such selection should include fertility results from lactating cows.  相似文献   

19.
Genetic parameters were estimated for protein yield (PY), clinical mastitis (CM), somatic cell score, number of inseminations (NI) and days from calving to first insemination (CFI) in first‐parity Swedish Red cows by series of tri‐variate linear animal models. The heritability of PY was moderate (0.34 ± 0.004), and the heritabilities of the functional traits were all low (0.014 ± 0.001–0.14 ± 0.004). The genetic correlation between CM and CFI (0.38 ± 0.05) was stronger than the correlation between CM and NI (0.05 ± 0.06), perhaps because CM and CFI usually are observed in early lactation when the cow is likely to be in negative energy balance, whereas NI generally is recorded when the cow is not in negative energy balance any more. The genetic correlation between NI and CFI was very close to zero (?0.002 ± 0.05), indicating that these two fertility traits have different genetic backgrounds. All genetic correlations between PY and the functional traits were moderate and unfavourable, ranging from 0.22 ± 0.02 to 0.47 ± 0.03. In addition, the effect of including genetic and phenotypic correlations between the trait groups milk production, udder health and female fertility on the accuracy of the selection index was quantified for a heifer, a cow and a proven bull. The difference between the accuracy obtained by multi‐trait and single‐trait evaluations was largest for the cow (0.012) and small for the heifer and the bull (0.006 and 0.004) because the phenotype of the cow for one trait could assist in predicting the Mendelian sampling term for a correlated trait.  相似文献   

20.
Because of the importance of reproduction in stock breeding systems, it is necessary to find selection criteria that increase reproductive efficiency. The aim of this study was to estimate genetic parameters for the probability of conception on first service (PROB) in Murrah heifers, and its association with other traits of economic interest [age at first calving (AFC), service period, calving interval and milk yield at 270 days], with the purpose of evaluating their use as selection criteria. Reproductive information and first lactation records of 1200 Murrah heifers were used to perform two‐trait analyses between PROB and the other characteristics. Bayesian inference was used to estimate the variance components, considering PROB as threshold and the other as linear factors. The results demonstrate that this trait has heritability of 0.15, indicating the possibility of a genetic gain by using it for selection. With respect to the genetic correlation estimates, the only high‐magnitude association was with AFC (?0.899), which is the current criterion indicating sexual precocity of females. In the light of the parameters estimated, the first‐service pregnancy rate is an alternative for indication of sexual precocity, although presenting a smaller genetic gain than the current standard AFC. Nevertheless, additional research should be conducted regarding this trait to assess the economic importance of its use in dairy buffalo production systems.  相似文献   

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