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1.
Objectives To identify risk factors for culling of dairy cows from eight New South Wales dairy herds.
Design A longitudinal population study of dairy cow culling in eight non-seasonally calving dairy herds in the Camden district of New South Wales. Cox's proportional hazards model was used to evaluate various risk factors for culling for a specific reason (sales, deaths, reproductive failure, disorders of the udder and low milk production).
Results Age at first calving was not a significant risk factor for culling. Milk production in the first lactation greater than the population mean did not influence length of productive life overall, but was associated with a greater hazard of removal for disorders of the udder. Risk of culling for reproductive failure differed significantly between farms, and was not related to events in the previous lactation such as calving-to-first service interval or calving-to-conception interval. Shorter calving intervals were associated with increased risk of removal for low milk production and disorders of the udder.
Conclusion Longitudinal surveys to accurately identify reasons for removal from a wide range of herds, identification of herds with low culling rates (especially for reproductive failure and udder disorders), and the identification of practices associated with these culling rates would be worthwhile to the Australian dairy industry.  相似文献   

2.
Objectives To describe the production and reproduction characteristics of the population under investigation and to compare them with the target population of non-seasonally calving dairy herds, to describe the pattern of culling with respect to length of productive life and length of time after calving, and to identify stages of the production cycle that are associated with increased risk of culling from the dairy herd.
Design A longitudinal population study of eight non-seasonally calving dairy herds in the Camden district of New South Wales.
Results The production and reproduction characteristics of this population were broadly similar to herds participating in the New South Wales Agriculture Dairy Herd Improvement scheme. In agreement with recent surveys, risk of culling increased with increased parity. This was accounted for specifically by increased risk of culling for calving disorders, reproductive tract lesions, and disorders of the udder. Risk of culling for failure to conceive appeared to remain constant throughout productive life. The overall risks for culling were greatest during the first 9 days after calving and 300 days after calving.
Conclusion Reducing the incidence of calving-associated disorders, attention to reproductive management and control of herd mastitis offer opportunities to reduce involuntary culling rates in this population.  相似文献   

3.
试验通过收集出生、产犊和离群的记录,探究宁夏地区荷斯坦牛成母牛的淘汰情况,分析影响该地区奶牛长寿性的因素。对15523头荷斯坦牛的生产寿命、在群寿命和利用胎次进行描述性统计,分析淘汰时的胎次、季节和泌乳阶段的分布情况;计算生产寿命、在群寿命和利用胎次之间的表型相关,利用固定模型分析场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性的影响。结果显示,宁夏地区荷斯坦牛的平均利用胎次为2.36胎,平均生产寿命为736.59 d。荷斯坦牛成母牛在产后第1个月内的淘汰风险最高,随着泌乳阶段的延长,成母牛在每个胎次内的淘汰风险均逐渐降低;随着淘汰胎次的增加,奶牛淘汰更加集中发生在产后泌乳早期;生产寿命、在群寿命和利用胎次之间存在较高的表型相关(均>0.9),场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性有显著影响(P<0.05),春季出生和22月龄头胎产犊的奶牛长寿性表现更好。本研究初步揭示了宁夏地区荷斯坦牛成母牛的淘汰规律和长寿性的影响因素,为宁夏地区牛群选育成母牛长寿性状奠定了基础。  相似文献   

4.
试验通过收集出生、产犊和离群的记录,探究宁夏地区荷斯坦牛成母牛的淘汰情况,分析影响该地区奶牛长寿性的因素。对15 523头荷斯坦牛的生产寿命、在群寿命和利用胎次进行描述性统计,分析淘汰时的胎次、季节和泌乳阶段的分布情况;计算生产寿命、在群寿命和利用胎次之间的表型相关,利用固定模型分析场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性的影响。结果显示,宁夏地区荷斯坦牛的平均利用胎次为2.36胎,平均生产寿命为736.59 d。荷斯坦牛成母牛在产后第1个月内的淘汰风险最高,随着泌乳阶段的延长,成母牛在每个胎次内的淘汰风险均逐渐降低;随着淘汰胎次的增加,奶牛淘汰更加集中发生在产后泌乳早期;生产寿命、在群寿命和利用胎次之间存在较高的表型相关（均>0.9）,场-出生年、出生季节、牧场规模、淘汰原因和头胎产犊月龄对长寿性有显著影响（P<0.05）,春季出生和22月龄头胎产犊的奶牛长寿性表现更好。本研究初步揭示了宁夏地区荷斯坦牛成母牛的淘汰规律和长寿性的影响因素,为宁夏地区牛群选育成母牛长寿性状奠定了基础。  相似文献   

5.
The objectives of this study were to determine the risk factors for development of postpartum ovarian cysts by evaluating several reproductive factors in individual cows, and to determine the economic impact of ovarian cysts on subsequent reproductive performance in dairy herds in Korea. The data, including cow parity, abnormal puerperium, endometritis, body condition score (BCS), and breeding status were collected from 634 cows in 9 dairy herds. We used logistic regression to evaluate the effects of these factors on ovarian cysts. A stepwise procedure, used to obtain the appropriate model with alpha=0.05, revealed that cow parity was the most important risk factor for ovarian cyst development within 8 weeks postpartum, while development of endometritis and BCS loss>or=1 from the dry period to 8 weeks postpartum were the most important risk factors for ovarian cyst development beyond 8 weeks postpartum. The occurrence of ovarian cysts beyond 8 weeks postpartum prolonged (P<0.01) the mean intervals from calving to first service (27 days) and conception (77 days), and increased (P<0.05) the culling rate (7.8%), while ovarian cyst development within 8 weeks postpartum did not affect (P>0.05) the mean intervals from calving to first service and conception or the culling rate. The economic loss resulting from the occurrence of ovarian cysts was estimated at approximately 823,996 won ($687) due to effects on the cost of nutrition, average growth of calves, labor and medical costs, and culling. These results suggest that cow parity is correlated with the development of ovarian cysts within 8 weeks postpartum, and endometritis and BCS loss>or=1 from the dry period to 8 weeks postpartum are correlated with the development of ovarian cysts after 8 weeks postpartum, which decreases reproductive performance and results in economic loss in dairy herds in Korea.  相似文献   

6.
An epidemiologic study of dystocia incidence in Swedish dairy cows, covering approximately 140 000 calvings, is presented. Various risk factors were identified. The Swedish Friesian Breed (SLB) had a higher incidence than the Swedish Red and White Breed (SRB), and first calving number had a higher incidence than subsequent calving numbers. SLB heifers younger than 28 months when calving had a higher risk of dystocia than older heifers. SRB heifers younger than 26 months when calving had a higher risk than older heifers. An association between parturient paresis and dystocia was demonstrated. Male calves and twinning increased the risk. A reduced risk during pasture as opposed to housing for cows from tied herds was found, but no difference between incidence for cows in tied herds and cows in loose housing could be demonstrated. Previous history of dystocia increased the risk of recurrence in subsequent calvings and also the risk of being removed during lactation.  相似文献   

7.
Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The applied Weibull proportional hazards model included time-independent effects of breed, housing from 3 to 7 months of age, number of housing changes before calving, grazing before 1st calving, herd median age at 1st calving, age at 1st calving, cow housing, herd lactational incidence risk of veterinary-reported clinical mastitis, and the random effect of herd. Time-dependent effects were year, month, the interaction year by month, parity, number of breedings, pregnancy status, the interaction parity by pregnancy status, herd mean milk-production level, relative milk yield within breed-parity, and veterinary-reported clinical mastitis. The lactation was divided into six stages in which pregnancy status was assumed to be known by the farmer and culling could occur. Median productive life time in culled cows was 780 d and 14% of the records were censored due to terminated data collection. An individual calving age of 28.2–30.9 months was associated with the highest culling risk, 1.2-fold higher than calving at ≤25.3 months, whereas the risk decreased almost linearly with a higher herd median age at 1st calving. Housing in slatted pens with >7 calves from 3 to 7 months was associated with a 1.7-fold increase in risk, relative to litter pens. If a cow had changed housing system 4 times before 1st calving it increased the risk of culling 1.4 times, relative to two housing changes. These results show that rearing factors affect the productive life time of dairy cows in Swedish family operations.  相似文献   

8.
Reproductive performance of Holstein dairy cows in Iran   总被引：2，自引：2，他引：0  
The objectives of the present study were to describe the current reproductive parameters of Holstein dairy cows in Iran and to determine factors which have a significant effect on reproductive performance with emphasis on high-producing dairy cows. Five large Holstein dairy herds from the major milk production areas of Iran were selected for this study. Reproduction data including parity of dam, calving date, days to first service, days open, number of services, dry period, and occurrence of diseases for cows that calved from 2004 to 2007 were collected from the herds' databases. To determine the effects of year and season of calving, disease status, level of milk production, and parity of dam on reproductive parameters, the proc-mixed procedure in SAS software was used. Overall, data about 8,204 lactation were collected for the study. Results showed that mean (±SD) days open, calving interval, and days to first service for study herds were 134 (±89), 403 (±86), and 67 (±38) days, respectively. Conception rates at the first service and the overall service-conception rate were 41.6% and 41%, respectively. The level of milk production and diseases had significant negative effects on days open and service per conception (P < 0.05); statistical analysis showed that for every 100-kg increase in milk yield, days open will increase by about 0.3 days. However, no significant effect of level of productivity was observed on days to first service. The results of this study indicate that high milk production is a risk factor for decreasing fertility in Iran, like many other parts of the world.  相似文献   

9.
The association between sole ulcer found at routine claw trimming 2–6 months after calving and reproductive, health and productive traits in the same lactation, was investigated in an observational study of 2368 dairy cows in 102 Swedish herds. The data were analysed by mixed multivariable linear-, logistic- and Poisson-regression modelling at the cow level, accounting for clustering within herd. Associations were found between sole ulcer and first-service conception risk in the first study year (OR 0.59), calving interval (2% longer), treatment for anoestrus (OR 1.61), and 305-day milk yield (479 kg ECM higher). No associations could be shown between sole ulcer and first-service conception risk in the second study year, the number of services per conception, clinical mastitis, high milk somatic-cell counts or culling.  相似文献   

10.
OBJECTIVE: To investigate relationships between biographic, reproductive, production and disease traits and subfertility among 965 Holstein cows from 10 non-seasonal calving dairy herds in the Camden region of New South Wales. DESIGN: A retrospective case-control study METHODS: Biographical, disease and reproductive data were collated from computerised records for cows with lactations that commenced between 1 July 1995 and 30 June 1996 and univariable and bivariable associations with subfertility were determined. RESULTS: Records from 965 cows that conceived were considered for risk factor analyses. Associations between subfertility and a number of risk factors (P < 0.3) were detected. Significant (P < 0.05) risk factors for subfertility in multiparous cows included herd of origin and, after controlling for the effect of herd, subfertility in the previous lactation, greater than 62 days dry, parity greater than five, interval between calving and first recorded heat, metritis and cystic ovarian disease. Herd of origin and, after controlling for herd effects, dystocia, metritis and percentage of milk fat plus protein at the time of first service were significant (P < 0.05) risk factors for subfertility in primiparous cows. The direction and magnitude of these associations are presented. CONCLUSION: Subfertility has a similar rate of occurrence in the herds examined to that reported overseas. Although herd of origin has a substantial effect on individual risk of subfertility, cow-level risk factors for subfertility are likely to exist. Exposures differ between primiparous and multiparous cows.  相似文献   

11.
To estimate the relationship between heat stress during the last 60 days prepartum, body condition score and certain reproductive traits in the subsequent lactation of Holstein cows, 564 multiparous cows and 290 primiparous cows from four dairy herds were used in a hot, humid region. Maximum prepartum degree days were estimated to quantify the degree of heat stress. Multiple regressions analyses and logistic regression analysis were performed to determine the effect of prepartum heat stress and body condition change on reproductive parameters, which were obtained from DHIA forms at the end of the lactation. Multiparous and primiparous cows which gained body condition score from calving to 60 d postpartum exhibited 28 and 27 fewer days open (P?<?0.05), respectively, than cows not gaining. There was no effect (P?>?0.05) of heat stress measurement on days open or services per conception in either multiparous or primiparous cows. During hotter months of calving, multiparous cows showed higher services per conception and primiparous cows showed higher days open and services per conception (P?<?0.05). Maximum prepartum degree-days were positively associated (P?<?0.05) with calving difficulty score. Multiparous cows with high body condition score at calving were 1.47 times more likely to present a very difficult calving than cows that calved in October (P?<?0.05). Collectively, these results suggest that reproductive performance was not affected by cumulative prepartum heat stress although it was associated with very difficult calving score.  相似文献   

12.
OBJECTIVE: To assess the association between the findings from vaginoscopic examination of postpartum dairy cows with peripartum reproductive disease and their subsequent reproductive performance, and to determine the factors that might be associated with a positive vaginoscopic examination (VV). METHODS: Cows (n=1325) from 17 seasonal calving dairy herds were enrolled if they had been calved at least 7 days and had at least one of the following conditions that placed them at risk of endometritis: retained fetal membranes (RFM), dystocia, a dead calf, hypocalcaemia, twin birth, calving induction or an observed vulval discharge (VD). Examination was undertaken 28-37 days before mating start date (MSD) within each herd. All cows were body condition scored (BCS) and were VV scored on a scale of 0 (clear) to 3 (purulent). The uterus and ovaries were assessed by rectal palpation. RESULTS: Cows with a positive VV score (1-3) were less likely to conceive to first service and had a lower pregnancy proportion than cows that had a negative VV score (score 0). Mean MSD to conception interval was longer in VV-positive cows. A positive VV score was associated with a low BCS, primiparity, intrapelvic uterus, poor uterine tone, large uterus, RFM, VD, dystocia, dead calf and twins. CONCLUSION: In the present study a positive VV score was associated with reduced reproductive performance and was more common in primiparous and low BCS cows. Of the at-risk cows, those with RFM, VD, dystocia, dead calf or twins were more likely to have a positive VV score.  相似文献   

13.
Calving records of Iranian Holsteins from April 1998 to September 2006 comprising 16 herds with 104 572 calving events representing 4045 twin births were used to evaluate reported open days, calving difficulties and calf birth weight in single‐ and twin‐births and the relationship exists between twinning and milk production. A logistic regression model was constructed to analyse dystocia for single‐ and twin‐births. In addition, statistical analyses of 305‐day milk yield, open days and calf birth weight were performed using the general linear models procedure. The odds of dystocia was greater after twin births [p < 0.0001; odds ratio (OR) = 2.32]. The odds of dystocia decreased from parity 1 to parity 2 and beyond (p < 0.0001; OR = 0.44). Open days were significantly different between single (129.28 days) and twin (144.88 days) births (p < 0.05). Calf birth weights were significantly greater for singletons than twins (43.33 kg vs. 34.36 kg; p < 0.05). In addition, twin‐calved cows had greater 305‐day milk production than single‐calved cows (p < 0.05). In general, development of practical management strategies to cope with the negative effects associated with twinning on dairies is critical, especially if the trend towards increased twinning in the dairy cattle population continues.  相似文献   

14.
Information on the losses associated with lower milk production and reproductive performance, as well as information from a survey of uk dairy herds using beef semen was used to estimate the economic importance of calving difficulties in uk dairy herds. The survey covered information on cow and calf mortality, cow culling and the need for veterinary assistance, the incidences of which were related to the degree of calving difficulty experienced. The total cost of a slightly difficult calving was estimated to be approximately 110 pounds, and of a seriously difficult calving between 350 pounds and 400 pounds, depending on assumptions of the veterinary costs. However, the major costs were associated with the labour required at the delivery, the increase in the number of days open, and the costs associated with the deaths of cows and calves, and cow culling.  相似文献   

15.
The study was undertaken to determine the trends in the reproductive performance of Holstein dairy cows in Iran during 1994 to 2008. Reproductive performance data for 528,034 lactations of 246,132 cows in 1,822 Holstein dairy herds of Iran were used. The potential effect of calving season, herd, parity, calving year, as well as herd size and 305-day milk production on reproductive performance traits was investigated using multiple regression models. The least squares means of age at first calving decreased by 3.1 (±0.06) days per year from 806.5 (±96.3) days in 1994 to 788 (±89.9) days in 2008. The least squares means of calving interval increased 1.02 (±0.03) days per year from 394.1 (±65) days in 1994 to 413.2 (±81) days in 2008. Greater 305-day milk production was associated with an average increase of 6.55 (±0.08) days in calving interval per 1,000-kg increase in milk yield. Larger herd size was associated with an average decrease of 0.22 (±0.02) days in calving interval per 50 cows per herd. The mean number of days dry was 88.6 (±51.3) days and increased by 0.82 (±0.02) days per year. In conclusion, reproductive performance in Holstein dairy herds has generally decreased, whereas herd size and milk production have increased over time. Producers may make significant improvements in herd reproduction by reviewing management strategies including the sire selection, reproductive management, inseminator training and techniques, and improved estrous detection. Moreover, it may be advisable for the fertility traits to be included in the genetic selection indices to reduce the rate of reproductive decline.  相似文献   

16.
The study was designed to determine the relation between β‐hydroxybutyrate (BHB) concentrations in milk from dairy cows after calving and the length of the previous lactation, the dry period and the 305‐day normalized production, and to assess the influence of BHB concentrations on culling and test‐day milk productions and somatic cell counts (SCC) throughout the lactation that followed the BHB measurement. The data used in the study were obtained from 59 187 cows in the Galicia region (Spain). BHB determination was performed using Fourier‐transformed infrared spectrometry from the milk samples collected from each cow on the first post‐partum test day. For statistical analysis, the following methods were applied: (i) ordinal regression to assess the effect of the length of the previous lactation, the dry period and the 305‐day normalized milk production on milk BHB, (ii) a Cox model to estimate the influence of the BHB concentration on risk of culling (overall and for a variety of reasons) and (iii) linear regression to assess the link between BHB and the milk yield and SCC obtained from each of the tests day performed throughout lactation. The probability of having higher BHB concentrations increased when the length of the previous lactation (p = 0.006), the dry period (p = 0.003) and the 305‐day normalized milk yield (p = 0.005) increased. However, the slight increase observed (especially for the case of the dry period and the 305‐day milk yield) would not justify that measures be implemented to reduce these traits. Higher concentrations of BHB led to an increased risk of culling due to ‘death’ (p ≤ 0.001) and ‘urgent slaughter’ (p ≤ 0.002) (both causes of involuntary culling). It also led to a reduction in milk production (p < 0.001) and an increase in SCC (p < 0.001) in the post‐partum; from that moment onward (including peak lactation), there were no differences in those two parameters depending on the BHB levels.  相似文献   

17.
Farm managers' decision to cull dairy cows is based on the cows' milk production, history of disorder(s), and reproductive performance, each of which affects dairy cows' lifetime (herd life and productive lifespan). We investigated the relationships among the incidence of clinical mastitis (CM), the reproductive performance, and the culling rate. We also assessed the effects of these relationships on the lifetimes of dairy cows, using the records made before and after the introduction of an automatic milking system (AMS) at Hiroshima University Farm. Milk yield, CM incidence density, and culling rate of dairy cows increased after the AMS introduction. The CM incidence was associated with an elongation of the calving interval in cows with the same parity. CM in the 1st parity might have caused the reductions of the cows' lifetime and their parity at culling. A higher age at first calving (AFC) was associated with an increase in culling rate but did not lead to a significant decrease in lifetime. Investigations of the factors mediating CM in the 1st parity or AFC with CM incidence or culling rate in the later stages might contribute to the control of lifetime of dairy cows.  相似文献   

18.
Non‐genetic factors influencing functional longevity and the heritability of the trait were estimated in South African Holsteins using a piecewise Weibull proportional hazards model. Data consisted of records of 161,222 of daughters of 2,051 sires calving between 1995 and 2013. The reference model included fixed time‐independent age at first calving and time‐dependent interactions involving lactation number, region, season and age of calving, within‐herd class of milk production, fat and protein content, class of annual variation in herd size and the random herd–year effect. Random sire and maternal grandsire effects were added to the model to estimate genetic parameters. The within‐lactation Weibull baseline hazards were assumed to change at 0, 270, 380 days and at drying date. Within‐herd milk production class had the largest contribution to the relative risk of culling. Relative culling risk increased with lower protein and fat per cent production classes and late age at first calving. Cows in large shrinking herds also had high relative risk of culling. The estimate of the sire genetic variance was 0.0472 ± 0.0017 giving a theoretical heritability estimate of 0.11 in the complete absence of censoring. Genetic trends indicated an overall decrease in functional longevity of 0.014 standard deviation from 1995 to 2007. There are opportunities for including the trait in the breeding objective for South African Holstein cattle.  相似文献   

19.
Our objective was to characterize the current reproductive performance and factors which may be related to it in the Fars province dairy herds in southern Iran. We collected retrospective data from four commercial herds in the region. All 256 cows with history of calving between 21 March 2004 and 20 March 2005 were followed until subsequent pregnancy, culling or death. Effects of risk factors on days open were investigated in a Cox proportional-hazards model. The overall median calving interval, dry period and days open were 388, 68, and 120 days, respectively. First-service conception risk and overall-service conception risk were 45 and 42%, respectively. Average numbers of insemination per pregnant and all cows were 2 and 2.1, respectively. Cows without incidence of any disorder during the lactation (but before conception, and including metabolic disorders) had 2.1-times greater hazard of conception than cows with incidence of disease. No significant association between calving interval, dry period, parity of dam, and sex and weight of calves with days open was observed.  相似文献   

20.
A total of 1,243 records for 585 dairy Friesian cows from 1997–2004 were used to study the factors affecting dystocia and its effects on reproductive performance and milk production. The overall incidence of dystocia was 6.9%. The percentage of dystocia decreased with increasing live body weight, age, and parity of cows (P < 0.05); however, it increased with increasing birth weight of calves (P < 0.05). The highest percentage of dystocia was detected in winter season, but the least percentage was in summer season (P < 0.05). The percentage of incidence of dystocia was significantly (P < 0.05) higher with winter feeding compared to summer ration (8.2% vs. 5.1%). The percentage of incidence of dystocia was significantly (P < 0.05) higher with twinning than single calving (15.5% vs. 6.5%), while not significantly affected by the sex of born calves. Incidence of dystocia had adverse effects on reproductive performance and milk yield. The service interval, service period, days open, and calving interval were significantly (P < 0.05) longer in cows afflicted with dystocia compared to normal cows. The conception rate was lower (P < 0.05), but the number of service per conception was higher (P < 0.05) in cows afflicted with dystocia compared to normal cows (60.5% vs. 73.0% and 3.4 vs. 2.7, respectively). Average daily milk yield was lower (P < 0.05) by 1 kg for cows with incidence of dystocia compared to normal cows.  相似文献   

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