Factors associated with rectovaginal injuries in Holstein dairy cows in a herd in Tehran, Iran

Rectovaginal injuries can result in subsequent infertility in cows. In a retrospective study, records of 147 Holstein cows with evidence of rectovaginal injuries were reviewed to determine the odds ratio (OR) of these injuries and their related risk factors. The study was conducted in a large dairy (typical herd size 1420 cows) in Tehran between the years 1993 and 1996. Period prevalences were 0.4% fistula, 1.9% laceration (third degree), 5.7% pneumovagina, 1.5% urovagina and 0.8% mixed injuries. The highest risk occurred among first-calf heifers. Animals with dystocia, first-calf heifers and male calves were at higher risk for rectovaginal injuries. We concluded that (1) handling dystocia with care might have a substantial role in reducing rectovaginal injuries, (2) first-calf heifers are to be under close observation and care during calving, and (3) because rectovaginal injuries reoccur in the next calving, cows with the history of these injuries should be monitored at the next labor.     

Culling of dairy cows. Part I. Effects of diseases on culling in Finnish Ayrshire cows.

The effects of 15 diseases on time until culling were studied in 39,727 Finnish Ayrshire cows that calved during 1993 and were followed until the next calving or culling. The diseases studied were: dystocia, milk fever, retained placenta, displacement of the abomasum, metritis, non-parturient paresis, ketosis, rumen disorders, acute mastitis, hypomagnesemia, lameness, traumatic reticuloperitonitis, anestrus, ovarian cysts, and teat injuries. Survival analysis, using the Cox proportional hazards model, was performed and diseases were modeled as time-dependent covariates. Different stages of lactation when culling can occur were also considered. Parity, calving season and herd were included as covariates in every model. Parity had a significant effect on culling, the risk of culling being four times higher for a cow in her sixth or higher parity than for a first parity cow. The effects of diseases varied according to when the diseases occurred and when culling occurred. Mastitis, teat injuries and lameness had a significant effect on culling throughout the whole lactation. Anestrus and ovarian cysts had a protective effect against culling at the time when they were diagnosed. In general, diseases affected culling decisions mostly at the time of their occurrence. The effect seemed to decrease with time from the diagnosis of the disease. However, milk fever, dystocia and metritis also had a significant effect on culling at the end of the lactation.     

Incidence and breed predilection for dystocia and risk factors for cesarean section in a Swedish population of insured dogs

OBJECTIVES: To estimate the incidence and breed predilection for canine dystocia using data from insurance claims. The risk factors for cesarean section (CS) were assessed for bitches with dystocia. STUDY DESIGN: Retrospective, longitudinal study. SAMPLE POPULATION: Insurance claims records (1995-2002) from a Swedish animal insurance database (Agria), including approximately 200,000 bitches. METHODS: The overall incidence rate of dystocia in insured bitches was calculated by dividing the number of reimbursed dystocia claims with the number of dog years at risk. Subsequently, incidence rates were stratified by breed, region, and habitat. The proportion of bitches with a dystocia claim that had CS were calculated, and risk factors for CS were assessed using a logistic regression model. RESULTS: Between 1995 and 2002, 3894 (2%) of 195,931 Swedish bitches included in the study had a reimbursed insurance claim for dystocia. The overall incidence rate of dystocia was 5.7 cases/ 1000 dog years at risk. Some breeds like the Scottish terrier were at increased risk of dystocia. Among bitches with dystocia, 63.8% were treated by CS. CONCLUSION: Dystocia in the bitch is more common than reported earlier. The risk of developing dystocia varies by breed, and a high percentage (63.8%) of affected bitches undergo CS. Clinical Relevance- Breeders and veterinarians could use this information to better predict which bitches are likely to experience dystocia and/or CS.     

A SURVEY OF DYSTOCIA IN BEEF CATTLE IN SOUTHERN QUEENSLAND

Data relating to dystocia were obtained for 22% of beef herds in the Roma region of southern Queensland. In 1973 dystocia incidence in 23,129 maiden heifers was 12%; 4% of heifers and 7% of calves died. Thirty-five per cent of the 444 herds surveyed had more than a 10% incidence of dystocia, and 10% had more than a 30% incidence of dystocia. Only 6% of herds had no dystocia. Among the 73% of producers considering dystocia a problem in most years, 14% regarded it as a major problem. The incidence of dystocia in heifers was significantly higher in Poll Hereford than Hereford herds, which in turn were higher than other breeds of cattle. Poll Hereford and Hereford owners were the most concerned about dystocia but did not supervise calving more frequently. Dystocia and attitude were also examined in relation to degree of supervision at calving and size of the breeding herd.     

Prevalence and risk factors for dystocia in dairy cattle: a review

This review focuses on the case definition of dystocia, its current prevalence and recent temporal trends, the different types of dystocia and their associated risk factors in dairy cattle. The reported dystocia rates in dairy cattle internationally are generally <5%, apart from those in the United States, where they are higher. Given the skewed distribution of herd dystocia rates, average figures mask high prevalence herds. Phenotypic dystocia trends are generally increasing internationally and this trend has been partially attributed to the introduction of Holstein genes. The principal types of dystocia differ between primiparae and pluriparae, with feto-pelvic disproportion (FPD) predominating in the former and fetal malposition in the latter. In order of importance, the two major determinants of FPD are calf birthweight and maternal pelvic size. Abnormal fetal position is most influenced by the number of fetuses, parity and calf sire breed. Adequate weighting of dystocia in selection indices, achievement of heifer rearing targets prior to both service and calving, and appropriate periparturient management decisions are prerequisites for controlling dystocia in dairy cattle.     

The predictive value of pelvimetry in beef cattle.

To elucidate reasons for failure of pelvimetry to predict dystocia, we collected data from 1146 heifers and 210 cows in five beef cow herds in Saskatchewan. We assessed the reliability of pelvic area measurements, the generalizability of findings, various modifications of the technique, and the statistical association between pelvic area measurements and dystocia. The repeatability (kappa) of pelvic area measurements between and within veterinarians for the Rice and Krautmann pelvimeters were low to moderate, indicating pelvic area measurements were imprecise. The positive predictive values and sensitivities of pelvic area measurements were consistently poor across herds, years of study, breeds of heifers, times of measurement, various pelvic area cut-off points, and sires. Various modifications of the technique, including pelvic area/calf birth weight ratios, pelvic area/heifer weight ratios, and Ko's calving prediction equation were also poor on-farm tests for predicting dystocia. Although the mean pelvic area in heifers with dystocia was smaller than those without dystocia, there was a large overlap in the distribution of their measurements. Far too many heifers with a small pelvic area had no dystocia (false positives) and far too many heifers with a large pelvic area had dystocia (false negatives) for pelvimetry to be useful. We conclude there is little evidence to justify the continued use of pelvimetry as an on-farm test to reduce dystocia in beef cattle.     

Factors affecting dystocia and birth weight in Grati cattle in Pujon,East Java

Summary

This paper discusses factors affecting dystocia and birth weight in Grati cattle in three villages in the Pujon district, East Java. Records of birth weight, dystocia score, village, season, parity, sex, artificial versus natural service, and age and weight of dam, were obtained from 268 parturitions. Village and weight of the dam had a significant effect on birth weight but not on dystocia. Parity had a significant effect on dystocia score. More abnormal births occurred with Al using exotic bulls. Calves from an abnormal birth were on average more than three kg heavier. First parity births combined with A1 with exotic bulls had a particularly high incidence of dystocia. It is concluded that farmers in Pujon can reduce the incidence of dystocia in heifers by using local bulls only.     

Factors affecting dystocia and birth weight in Grati cattle in Pujon, East Java

This paper discusses factors affecting dystocia and birth weight in Grati cattle in three villages in the Pujon district, East Java. Records of birth weight, dystocia score, village, season, parity, sex, artificial versus natural service, and age and weight of dam, were obtained from 268 parturitions. Village and weight of the dam had a significant effect on birth weight but not on dystocia. Parity had a significant effect on dystocia score. More abnormal births occurred with AI using exotic bulls. Calves from an abnormal birth were on average more than three kg heavier. First parity births combined with Al with exotic bulls had a particularly high incidence of dystocia. It is concluded that farmers in Pujon can reduce the incidence of dystocia in heifers by using local bulls only.     

Risk factors for dystocia in farmed red deer (Cervus elaphus).

OBJECTIVE: To analyse data from a study of deer herd health and productivity to identify potential risk factors for the occurrence of dystocia. DESIGN: A 2-year longitudinal observational study of 14 red deer farms was carried out in New Zealand. About 2700 hinds were monitored each year for individual characteristics including body condition score (BCS), and reproductive performance. Grazing and calving management practices were recorded. During calving, farmers recorded calving difficulties (dystocia) that needed human assistance or caused the death of the hind. Risk factors potentially affecting the occurrence of dystocia were identified and analysed by multivariable statistical techniques. RESULTS: The percentage of hinds with dystocia was 0.52% (95% CI 0.32 to 0.78). Hinds with a post-winter BCS over 3.5 were 2.7 times as likely to experience dystocia as hinds scoring 3.5 or less. Given the same BCS class, bodyweight gain in late pregnancy was associated with an increased risk of dystocia. Grazing steep paddocks in the last trimester of pregnancy decreased the risk of dystocia in hinds with a BCS over 3.5. CONCLUSIONS: The risk of dystocia on red deer farms may be reduced if key individual animal, management and environmental factors are optimal.     

Common Peripartum Problems in the Mare

Reproductive problems in the perinatal period can adversely affect a mare's future fertility or, worse, may be life threatening to her or her foal. A number of abnormalities can occur, including uterine torsion, uterine artery or uterine hemorrhage, retained fetal membranes, metritis, rectovaginal injuries, and necrotic vaginitis. Because hemorrhage, retained placenta, metritis, and necrotic vaginitis can happen after a normal delivery or after dystocia, all mares should be monitored closely in the first days after parturition for signs of lethargy, depression, colic, sore feet, or anorexia. Methods for diagnosing, managing, and treating these conditions and the possible complications are discussed.     

Dystocia in Friesian mares: Prevalence,causes and outcome following caesarean section

Friesian horses appear to suffer a relatively high incidence of dystocia but there are, to the authors' knowledge, no published reports on the incidence or types of dystocia in Friesian horses. A retrospective survey of clinical details and post treatment recovery was performed for 66 mares referred to Wolvega Equine Hospital for dystocia during 2001–2006. Friesian mares appear to be particularly prone to dystocia due to fetal ankylosis or transverse presentation. However, despite dystocia of relatively long duration prior to caesarean section, post operative survival and fertility of mares and, more surprisingly, survival of foals were similar to those reported in surveys for other breeds.     

母牛难产的风险病因--基于系列案例研究

[目的]难产是繁殖母牛的常见疾病,危害母牛和犊牛健康,进行难产牛原因分析有助于兽医或者牛场做好接产工作,提高生产力。 [方法]在万方数据服务平台、CNKI中国知网、Elsevier SD数据库和“SCI-科学引文索引”上,用关键词“难产”、“病例”、“牛”精确搜索我国相关的案例,统计筛除后的病例数,对牛难产原因进行统计和分析。 [结果]检索获得母牛难产的病例总数为753例,难产原因占比最大的是胎儿性难产有525例,占69.72%(95%CI 66.3-73.0);其次是产道异常（骨折造成骨盆畸形,子宫颈、阴道、阴门狭窄造成的产道异常）造成的难产89例,占11.82%(95%CI 9.6-14.3);阵缩及努责无力造成的难产41例,占5.44%(95%CI 3.9-7.3);子宫扭转造成的难产38例,占5.05%(95%CI 3.6-6.9);子宫颈开张不全造成的难产26例,占3.46%(95%CI 2.3-5.0);营养不良造成的难产18例,占2.39%(95%CI 1.4-3.8);双胎难产9例,占1.20%(95%CI 0.5-2.3);人为因素和其他因素造成的难产有7例,占0.93%（95%CI 0.4-1.9）。 [结论]引起母牛难产的最主要的因素是胎儿性难产、产道异常。兽医在实际临床中,应快速、准确确定母牛难产的病因,采取对应接产措施,减少经济损失。     

THE INCIDENCE OF DYSTOCIA IN FINE-WOOL MERINO EWES

The mean incidence of dystocia in 1,510 fine-wool Merino ewes over a ten-year period was 4.1% of ewes lambing. In the 10 year period, 10% of all neonatal mortality was attributed to dystocia and in only 23% of dystocias was lamb presentation abnormal. The incidence of dystocia was not related to age of ewe. Significantly more ewes experienced dystocia at spring than winter (P less than 0.05) or summer (P less than 0.01) lambings. The mean birth weights of dystocic single and twin born lambs were 4.19 and 3.38 kg respectively. The corresponding birth weights of lambs that did not experience dystocia were 3.69 and 3.00 kg. More ewes experienced dystocia when stocked at 12 or 16 per ha than at 8 per ha (P less than 0.05). Fifty per cent of recorded dystocias occurred in ewes stocked at 16 per ha, 40 per cent at 12 per ha and 10 per cent at 8 per ha. Ewe body weight pre-lambing was not related to the incidence of dystocia but it would appear that weaker ewes are more likely to have a difficult birth than ewes that are stronger and in better condition.     

Dystocia in beef heifers: a review of genetic and nutritional influences

Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have not adopted the practice. The predominant type of dystocia affecting 2-year-old heifers is feto-maternal disproportion, a condition in which the fetus is too large relative to the size of the heifer's pelvis. Reducing birthweight of the calf is a means of reducing the incidence of dystocia. Birthweight and length of gestation are determined by genotype of the calf, maternal genetic effects and environmental effects. Bulls with low estimated breeding values for birthweight have been selected for mating heifers; however, the positive genetic correlation between birthweight and mature weight meant that the progeny of these bulls tended to be lighter at finishing, making them less desirable in the beef industry. The genotype of the dam also plays a role in determining the risk of dystocia; the maternal ability of the dam to nurture the fetus influences birthweight, and the dam's genetic potential for growth influences the size of her pelvic area. Heavy heifers tend to produce high birthweight calves, counteracting the reduction in the incidence of dystocia resulting from the larger pelvis in larger heifers. Manipulating feeding level during pregnancy offers an alternative method for manipulating the birthweight of calves. Little is known about the effects of nutrition in early gestation on placental development or birthweight of calves. No differences in the birthweight of calves have been observed in response to variation in feeding in mid-pregnancy, and variable responses in birthweight and the incidence of dystocia to feeding in the third trimester of pregnancy have been reported. Differences in birthweight have not always resulted in differences in the incidence of dystocia, primarily due to differences in liveweight of the heifer also induced by feeding regimens. Variability in the incidence of dystocia in response to feeding level in the third trimester of pregnancy makes it difficult to make recommendations for the feeding of heifers at this stage of gestation. More research is needed into the effects of nutrition in early gestation on fetal and placental development in cattle.     

Dystocia in a referral hospital setting: approach and results

REASONS FOR PERFORMING STUDY: Dystocia in the mare is an emergency in which duration has a profound effect on survival of the foal. Specific examination of the effects of dystocia duration on foal survival provides information to enable horse care personnel and veterinarians to manage these cases more effectively and maximise the chances of obtaining a live foal. HYPOTHESIS: Dystocia duration would have a negative impact on foal survival while method of dystocia resolution would not have an effect on foal survival. Additionally, we were interested in determining the effects of dystocia on subsequent fertility. METHODS AND RESULTS: In the years 1986-1999, 247 dystocias were admitted. Of these, 91 % resulted in survival and discharge of the mare, 42% in delivery of a live foal, and 29% of foals survived to discharge. Period from hospital arrival to delivery for foals alive at discharge (23.0 +/- 14.1 mins) was not significantly different than for foals not surviving (24.8 +/- 10.6 mins) (P > 0.05); and from chorioallantoic rupture to delivery for foals alive at discharge (71.7 +/- 343 mins) was significantly less than for foals not surviving (853 +/- 37.4 mins) (P < 0.05). Average predystocia live foaling rates for all mares with available records was 84%. Overall post dystocia live foaling rates over the entire period of this study were 67%. Of mares bred in the year of the dystocia, 59% had a live foal in the year following. CONCLUSIONS: Based on these results, dystocia duration has a significant effect on foal survival and resolution methods should be chosen to minimise this time, as the difference between mean dystocia duration for foals that lived and those that did not in this study was 13.6 mins. Post dystocia foaling rates reported here are higher than previously reported for both same-season and overall breedings, indicating same-season breeding may be rewarding for select dystocia cases. POTENTIAL RELEVANCE: Dystocia resolution methods that minimise delivery time may maximise foal survival. Post dystoicia breeding may be rewarding in select cases.     

Dystocia in beef heifers: A review of genetic and nutritional influences

Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have not adopted the practice. The predominant type of dystocia affecting 2-year-old heifers is feto-maternal disproportion, a condition in which the fetus is too large relative to the size of the heifer's pelvis. Reducing birthweight of the calf is a means of reducing the incidence of dystocia. Birthweight and length of gestation are determined by genotype of the calf, maternal genetic effects and environmental effects.

Bulls with low estimated breeding values for birthweight have been selected for mating heifers; however, the positive genetic correlation between birthweight and mature weight meant that the progeny of these bulls tended to be lighter at finishing, making them less desirable in the beef industry. The genotype of the dam also plays a role in determining the risk of dystocia; the maternal ability of the dam to nurture the fetus influences birth- weight, and the dam's genetic potential for growth influences the size of her pelvic area. Heavy heifers tend to produce high- birthweight calves, counteracting the reduction in the incidence of dystocia resulting from the larger pelvis in larger heifers.

Manipulating feeding level during pregnancy offers an alternative method for manipulating the birthweight of calves. Little is known about the effects of nutrition in early gestation on placental development or birthweight of calves. No differences in the birthweight of calves have been observed in response to variation in feeding in mid-pregnancy, and variable responses in birthweight and the incidence of dystocia to feeding in the third trimester of pregnancy have been reported. Differences in birthweight have not always resulted in differences in the incidence of dystocia, primarily due to differences in liveweight of the heifer also induced by feeding regimens. Variability in the incidence of dystocia in response to feeding level in the third trimester of pregnancy makes it difficult to make recommendations for the feeding of heifers at this stage of gestation. More research is needed into the effects of nutrition in early gestation on fetal and placental development in cattle.     

Retrospective study of dystocia in mares at a referral hospital

REASONS FOR PERFORMING STUDY: The period between the onset of dystocia and its resolution has an important bearing on fetal outcome. There are few published data on which to base decisions regarding optimum management of cases in practice. OBJECTIVES: To evaluate and compare the effects of a coordinated dystocia management protocol (CDMP) with that of a previous protocol of random management on time to resolution and outcome in both an emergency dystocia referral population of mares (referred emergency cases: EM) and in a population of mares residing in hospital due to high risk pregnancy (HRP) concerns that then experience dystocia at parturition. METHODS: Retrospective study performed at a university hospital referral centre of cases presenting from 1991-2004 divided into Group 1 (pre-CDMP) and Group 2 (CDMP). RESULTS: Medical records of 71 cases with dystocia were retrieved and data recorded. For referred emergency cases (EM), time from hospital presentation to resolution decreased significantly by 32 min (P = 0.03) after institution of CDMP. Survival rate of mares at discharge was 86%. Survival of EM foals was low, with 10% in Group 1 and 13% in Group 2, surviving to discharge. For EM foals delivered alive, survival to discharge was 30% and 43% in Groups 1 and 2, respectively. Median Stage II was significantly (P < 0.001) different at 71 and 282 min for EM foals delivered alive vs. those not alive at delivery, respectively. Median duration of Stage II was also significantly (P < 0.001) different between EM foals surviving and not surviving to discharge, at 44 and 249 min, respectively. Survival of HRP dystocia foals to discharge was 79%. CONCLUSIONS: Although CDMP reduced the time from presentation at the hospital to resolution significantly for EM, total duration of Stage II for EM was unchanged, as was foal outcome. POTENTIAL RELEVANCE: Very early referral of mares with dystocia to referral centres with dystocia management protocols may improve fetal outcome as increased duration of Stage II in the horse affects fetal outcome negatively.     

Effects of twinning on gestation length, retained placenta, and dystocia

Constraints to maximal productivity from twinning in beef cattle include increased incidence of dystocia and retained placenta, longer postpartum interval, and lower conception rate. Incidence and cause(s) of the shorter gestation length and of the increased retained placenta and dystocia associated with twinning were evaluated for 3,370 single and 1,014 twin births produced in a population of cattle selected for natural twin births. Gestation length was shorter for twin than for single pregnancies (275.6 vs. 281.3 d, P<.01) and likely contributed to the higher incidence of retained placenta associated with twin births (27.9 vs. 1.9%; P<.01). Incidence of retained placenta was also higher in the spring (March-April) than in the fall (August-September) calving season (18.3 vs. 11.4%; P<.01). The higher incidence of dystocia with twins than with singles (46.9 vs. 20.6%, P<.01) was primarily due to abnormal presentation (37.0 vs. 4.5%, respectively) of one or both twin calves at parturition. First- (40.5%) and second- (22.7%) parity dams with a single birth had more (P<.01) dystocia than older dams (13.4%), whereas dystocia was not affected (P>.10) by parity with twin births. Because of the shorter gestation length and the increased incidence of retained placenta and(or) dystocia, achievement of increased productivity with twinning in cattle necessitates intensive management of twin-producing dams and their calves during the calving season. Management of the increased dystocia can be facilitated by preparturient diagnosis of twin pregnancies, enabling timely administration of obstetrical assistance to facilitate delivery of twin calves and to increase their neonatal survival.     

Radiographic pelvimetry for assessment of dystocia in bitches: a clinical study in two terrier breeds

Radiographic pelvimetry was used to assess the role of pelvic anatomy in obstructive dystocia in bitches. Based on the history of previous whelpings, 20 Boston terrier and 14 Scottish terrier bitches were divided into two equal groups: normally whelping bitches and bitches with obstructive dystocia. Additional whelpings during the period of study were closely observed and the pups were immediately weighed and measured. The bitches were clinically examined and the pelvis was radiographed in ventrodorsal and lateral projections. Measurements from the radiographs showed a significantly smaller pelvic size in the bitches with obstructive dystocia compared to the normally whelping bitches. Fetal-pelvic disproportion in the Scottish terrier was mainly due to a dorsoventrally flattened pelvic canal, whereas in the Boston terrier it arose from the combination of a dorsoventrally flattened pelvic canal and big fetuses with large heads. These results suggest that radiographic pelvimetry could be used to predict a disposition for dystocia in individual bitches, and as a basis for selection of breeding animals.     

亚洲象难产转化一例

通过对昆明动物园一头16岁的亚洲象分娩过程，对其由初、中期出现难产症状转化为顺产过程的观察，认为分娩时间超过1h后胎儿迟迟不产出，即可判定发生了某些难产。提出应加强对象等大型、珍稀动物繁殖期的特殊饲养管理，逐步建立针对性的专用兽医技术，才能减少难产发生时的盲目性，提高处置决策正确率。