The use of clenbuterol in large animal obstetrics: manual correction of bovine dystocias.

This study was undertaken to test the effect of clenbuterol, a smooth muscle relaxant, as an aid for the manual correction of bovine dystocias in a rural Quebec practice. The drug was given initially by intravenous coccygeal or jugular injection at a dose of 0.6 micrograms-0.8 micrograms/kg of body weight to parturient cows affected with fetal malpresentations (n = 37), malpostures (n = 112), or uterine torsions (n = 70). These cases comprised 32% (219/688) of the manually corrected dystocias encountered in cattle during the trial. Ease provided for obstetrical maneuvers of different types of dystocias was the evaluation criteria used in this report. The drug's myometrial relaxant effect made corrections easier for the veterinarian, and shorter and less traumatic for the dam. The success rates achieved for vaginal corrections and delivery of uterine torsions were 84% (76/91) and 77% (70/91), respectively. Other recorded benefits included the need for less frequent use of epidural anesthesia and a significantly lower incidence of retained fetal membranes (chi 2 = 11.18, p < 0.001). No adverse reactions were observed at any time. Clenbuterol proved to be a useful drug for manual correction of dystocias in cattle.     

Uterine torsion in cattle - frequency, clinical symptoms and theories about the pathogenesis

Aim of the present study was to summarize the available literature about the incidence, frequency, clinical symptoms and ideas as to the pathogenesis of uterine torsion in the cow. MATERIALS AND METHODS: Analysis of the literature using electronic libraries (Pub Med, Medline), German veterinary medicine journals and obstetrical textbooks. RESULTS: Uterine torsion is a very important maternal reason for dystocia as most cases occur during parturition. The post-cervical torsion (combined uterine and vaginal torsion, Torsio uteri and vaginae) is more commonly diagnosed than an intra-cervical or pre-cervical torsion. Torsions to the left occur more frequently than to the right. Clinical symptoms clearly vary depending on the degree of torsion. The frequency in relation to all parturitions is described as between 0.5 and 1%, whereas the percentage of uterine torsions presented to the veterinarian as a reason for dystocia varies between 2.7 and 65%. The pathogenesis of uterine torsion remains unclear; however, general agreement exists that the cow is predisposed to uterine torsion due to its anatomy. It appears that the Brown Swiss is more often affected than other cattle breeds.     

The use of clenbuterol for the management of large animal dystocias: surgical corrections in the cow and ewe

Clenbuterol (Ventipulmin® Solution) was included in the corrective management of dystocia cases requiring obstetrical surgery encountered in a Quebec rural practice. Data were collected on a total of 69 cases: 63 bovine and three ovine caesareans, and three bovine fetotomies. Ease of exteriorization of the gravid uterus and postoperative development of uterine adhesions were compared in two groups of bovine caesarean cases: a clenbuterol-treated group (Group A, n = 63) and a nontreated control group (Group B, n = 90). Clenbuterol produced a potent myometrial relaxant effect making its use beneficial in the correction of the bovine and ovine dystocias. It provided significantly improved uterine maneuverability (ײ = 47.63, P < 0.001) and significantly reduced postoperative development of adhesions (ײ = 14.05, P < 0.001) except in bovine caesarean cases with a high degree of myometrial distension. Neonatal and maternal health were not impaired and retention of fetal membranes was not increased. When used as directed, clenbuterol was a safe, reliable, and efficacious drug.     

COMPARISON IN THE SAME ENVIRONMENT OF CALVING PROBLEMS IN HEIFERS FROM HERDS WITH A HISTORY OF A LOW AND HIGH INCIDENCE OF DYSTOCIAS

The incidence of dystocias and the calving performance of primiparous Hereford heifers from 2 herds, one with a low (A) and the other a high (B) dystocia history, were compared when all animals were run on the same property in southern Queensland.
The dystocia incidence was 21.4% for Herd A heifers and 40.5% for Herd B heifers (P≅0.10). While Herd A heifers had significantly (P<0.05) heavier calves than Herd B heifers (29.1 v 27.7 kg), the ratio of calf birth weight to dam pelvic brim area was 0.11 kg/cm² for both groups. Differences in the size of the maternal pelvis, calf oversize and the type of presentation recorded for assisted births did not satisfactorily explain the difference in the incidence of dystocias. The circumstantial evidence indicated that inherent factors may affect dystocia.     

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.     

Etiology of torsio uteri in cattle: a review

An overview about various observed phenomena, assumptions, and relations concerning the development of uterine torsion in cattle is presented. Furthermore, contradictory observations and old ideas are relativated and more accurate interpretations are given. It is known that the fetus himself is moving what is considered a reason for a torsion of the uterus. Intrauterine movements of the fetus are physiologic, and therefore other factors for uterine torsions are likely to be involved. A very plausible explanation for the selective occurrence of uterine torsion in cattle seems to be decreased amniotic fluid in relation to the size of fetus and uterus, because other influences can also be observed in all or at least in a high number of other animals. Destabilizing factors concerning the uterus (tonus decreased, uterus outside bursa supraomentalis) increase the possibility of developing a torsio uteri but are not compelling for the torsio uteri.     

Patterns of stillbirth and dystocia in Ontario cow-calf herds.

The association between a number of individual animal and herd level factors and calving problems in beef cows and heifers were examined. Data were from the 1987 calving season for a subset of 123 herds which maintained individual-animal records, from a sample of 180 randomly selected Ontario cow-calf herds. The median herd dystocia rate was 5.8% and 24.4% of herds had no dystocias. The median herd stillbirth rate was 2.8%, and 33.3% of herds had no stillbirths. Dystocias and stillbirths were much more common in heifers than in cows. Separate statistical models of dystocia and stillbirth for cows and heifers were created. Dystocia in cows was associated with calf sex, previous calving assistance and large breed type and birth weight. Variations in 1987 cow herd dystocia rates were associated with calving season, location and density, and the herd dystocia rate in 1986. Dystocia in heifers was associated with large breed type and calf birth weight. Herd-level management practices associated with increased heifer dystocia rates included breeding heifers to calve earlier than cows and rearing heifers together with the cow herd. Stillbirths for both cows and heifers were associated with calving assistance, particularly hard assistance. Herd-level management and other factors were unassociated with stillbirths.     

Influence of uterine torsion in water buffaloes (Bubalus bubalis) with insights into the hematological and biochemical prognostic values regarding to manual correction

Bovine uterine torsion refers to the rotation of the gravid uterus around its longitudinal axis. It is the dominant cause of dystocia in buffaloes. A total of two hundred and seventeen dystocia’s Egyptian buffaloes were examined, and another twenty were apparently normal at the full term (healthy pregnant group). From the dystocia’s buffaloes, twenty-three percentage (n = 50) was uterine torsion after gynecology inspection at presentation (Ut group) and 5 days after the manual correction (Utc group). The buffaloes with uterine torsion exhibited loss of appetite, constipation, colic, and straining. The incidence of torsion was mostly at first parity that accounting for 50% of cases. Regarding to the pregnancy stage, torsion mostly occurred at full term, where it primarily occurred in buffaloes at 3 years of age. Right-sided torsion ensued in 90% of all cases. The survival rate of the pregnant buffaloes was 90% (45 buffaloes), and 10% (5 buffaloes) was directed to the culling. Regarding to the fetal survival outcome, 30% of fetuses was survived where the other 70% was died. The hematological results denoted leucocytosis in Ut and Utc groups that attributed to neutrophilia, monocytosis, and eosinophilia. Biochemical assessments were denoted an augments in the levels of serum AST, LDH, CPK, creatinine, blood urea nitrogen, progesterone, cortisol, MDA, NO, TAC, blood lactate (bLac), TNF-α, and IL-6. Where there were a non significant fluctuations in the ALT, GGT, calcium, and phosphorus levels in the torsion cases. The significant declines in 17-β-oestradiol, total proteins, albumin, magnesium, and GSH levels in the dams suffering from Ut were observed. The robust elevations in AST (156 ± 3.47) and bLac (16.12 ± 0.18) with severe hypomagnesaemia (2.69 ± 0.15) were evident in 10% of the torsion cases that directed to the culling. This can conclude that robust elevations in AST and bLac with severe hypomagnesaemia are factors denoting a poor prognosis for uterine torsion in the buffaloes.

     

On-the-farm incidence and nature of equine dystocias

The characteristics of parturition and dystocia were recorded on standardized forms by foaling attendants on 8 farms for 517 spontaneous parturitions. Dystocias were classified from examination of the forms into those with malposition (involving the fetal body), malposture (involving fetal extremities), and normal position and posture in which traction was considered essential. Dystocias occurred in 58 of 517 (11.2%) parturitions and involved normal fetal position and posture (31.0%), malposition of body (22.6%), and malposture of extremities (41.4%). Other recorded frequencies were for emergence of an intact chorioallantois at the labia (2.0%), hiplock (1.2%), posterior presentation (0%), uterine torsion (0%), deformed fetal limbs *8.4%), stillbirth (1.2%), death of foal within 24 hours (1.2%), life-threatening injury to the mare (1.5%), and retained placenta (13.5%). The frequencies of a prolonged or excessive Stage 1 culminates in rupture of chorioallantois, (11.5%), deformed foal limbs (24.0%), relatively large foal (26.8%), and retained placenta (22.0%) were greater (P<0.05) for mares with dystocia than for mares without dystocia (2.6, 6.7, 7.9 and 10.5%, respectively).Ten of 14 (72%) dystocias with normal position and posture were attributable to a relatively large foal or weak maternal contractions. All of 16 malpositions of the body involved a tendency toward the dorso-pubic position (upside-down) and 31% were accompanied by malpostures of the extremities. Observations suggested that alternate standing and lying by the mare played a role in preventing and aiding in the self-correction of malpositions. Most (55%) of 24 malpostures involved retention of a front foot. The primary indicators of a problem were the absence of any fetal parts or membranes at the labia for a prolonged time after rupture of the chorioallantois (28% of dystocias) or the emergence of only one foot (34%).The interval from foal delivery to placental discharge was shorter (P<0.01) for Miniature Horses (17±3 min; n=17) than for the larger breeds (54±2 min; n=395). In 3 of 19 (16%) miniatures, the placenta and foal were delivered simultaneously. It was judged necessary to rupture manually an intact amnion in 2 of 5 miniatures on one farm.     

Clinical signs and treatment of chronic uterine torsion in two mares

Two mares were evaluated because of chronic uterine torsions of 2 and 4 weeks' duration; both were pyrectic, anemic, tachycardic, and anorectic, had signs of depression, and had an abnormal uterus and contents on transrectal examination. Both mares underwent cesarean section for lysis of adhesions from the uterus to the peritoneum, correction of the torsion, and ovariohysterectomy Both mares recovered with only minor complications and returned to be used as riding horses. Chronic uterine torsion should be considered in mares in late stages of gestation that have vague clinical signs and transrectal palpation findings that are unlike those described in typical cases of uterine torsion. Prognosis for life can be good after treatment by ventral midline celiotomy, cesarean section, correction of the torsion, and ovariohysterectomy.     

A Cross-sectional Study of Reproductive Performance of Smallholder Dairy Cows in Coastal Tanzania

A retrospective cross-sectional study was conducted on 200 randomly selected smallholder farms from a mixed dairy farming system in Tanga, Tanzania, between January and April 1999. We estimated the frequency and determinants of long calving interval (LCI), retention of fetal membrane (RFM), dystocia, and abortion in smallholder crossbred cattle and explored birth trends. The mean calving interval was 500 days and birth rate was 65 per 100 cow-years. Dystocia was reported to affect 58% of calvings, and 17.2% of animals suffered RFM. Using mixed effect models, the variables associated with LCI, RFM and dystocia were breed, level of exotic blood and condition score. Zebu breeding was associated with LCI (odds ratio (OR) = 2.3, p = 0.041) and Friesian breeding with lower odds for RF (OR = 0.26, p = 0.020). Animals with higher levels of exotic blood had lower odds for evidence of dystocia (OR = 0.45, p =0.021). Evidence of dystocia was significantly associated with poor condition score (P = −1.10, p = 0.001). Our observations suggest that LCIs are common in smallholder dairy farms in this region and a likely source of economic loss. Dystocia, RFM, poor condition score and mineral deficiency were common problems and were possibly linked to LCI.     

An investigation into dystocia in a south country Cheviot flock.

An abnormally high incidence of dystocia was encountered in the south country Cheviot flock at the Hill Farming Research Organisation's research station at Sourhope, Yetholm, Roxburghshire over the past four years, 1970 to 1973. Lambing records were only available for 1972 and 1973 for Sourhope ewes and gimmers of all breeds and showed the following: (see article) This meant that in terms of attention and vigilance, a high shepherding input was necessary with the South Country Cheviot flock. Intensive observation and measurements of some relevant parameters were therefore made in the gimmer age group of this flock, numbering 126, during the lambing season of 1974; 39-7 per cent required assitance. This paper describes the behavioural pattern in lambing and demonstrates differences between those animals which were assisted and those which were not. The features of the dystocias and their possible cause are discussed.     

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.     

Prevalence of and risk factors associated with the presence of Sarcocystis neurona sporocysts in opossum (Didelphis virginiana) from Michigan: a retrospective study

From April 1996 to December 2002 the prevalence of Sarcocystis neurona sporocysts in North American opossum (Didelphis virginiana) in Southern Michigan was estimated. Sporocysts of S. neurona were found in intestinal scrapings from 31 (15%) of 206 examined opossum. The frequency of infection was higher in adult animals (26/206; 12.6%) and females (19/206; 9.2%) than in juveniles (5/206; 2.4%) and males (12/206; 5.8%). Also, prevalence of S. neurona sporocysts in opossums in relation to factors such as age, sex, season, body condition, presence of concomitant infection, and presence of young in the pouch of females was studied in detail over the course of the year, 2002. Univariate analyses identified the following factors as being associated with the presence of S. neurona sporocysts in opossums: (i) for age, adult (odd ratio [OR] = 2.074, P = 0.0005); (ii) for sex, female (OR = 7.016, P = 0.0119); (iii) for season, summer (OR = 7.917, P = 0.0032) and spring (OR = 4.071, P = 0.1063); (iv) for body condition, poor (OR = 3.50, P = 0.1200) and good (OR = 1.167, P = 0.8637); (v) for the presence of concomitant infection (OR = 23.056, P = 0001), and (vi) for the presence of young in the pouch of females (OR = 40.083, P = 0.0001). Multivariate logistic-regression analyses selected the following factors as being significantly associated with presence of S. neurona sporocysts in opossums: (i) for the presence of concomitant infection (OR = 8.722, P = 0.0160) and (ii) for the presence of young in the pouch of females (OR = 31.915, P = 0.0065). The prevalence of S. neurona sporocysts in D. virginiana suggests that this opossum may constitute an ample reservoir of infection to other animals in the northern United States.     

Uterine torsion of 720 degrees in a midgestation cow

A 720 degrees uterine torsion was diagnosed in a cow at 161 days of gestation. The uterine torsion was reduced by laparotomy and intra-abdominal manipulation. An emphysematous fetus was removed vaginally. The cow was treated medically for associated metritis and peritonitis. Uterine torsions in cattle most commonly occur at parturition and only rarely exceed 360 degrees.     

Ventral midline caesarean section for dystocia secondary to failure to dilate the cervix in three alpacas

Three alpacas that presented with dystocia characterised by failure of the cervix to dilate, underwent caesarean section. Surgery on each animal was performed through a ventral midline incision under general anaesthesia. Two live crias were delivered and one cria was dead at delivery. All three alpacas had retained foetal membranes for a period of 12 h to 4 d and one developed uterine prolapse, which was replaced using sedation and epidural anaesthesia. There were no complications associated with the surgical procedure and all three alpacas went on to have confirmed pregnancies. Caesarean section through a ventral midline incision should be considered an alternative for treatment of difficult dystocias in alpacas.     

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 effect of uterine torsion on mare and foal survival: a retrospective study, 1985--2005

REASONS FOR PERFORMING STUDY: Anecdotal speculation suggests that prognosis for survival of mares and foals following correction of uterine torsion has improved over the past 30 years. OBJECTIVES: To determine statistically the outcome of uterine torsion according to duration of clinical signs, stage of gestation, parity, physical examination findings, method of correction, prognosis for survival and reproductive health of the mare, and prospects for the foal within the neonatal period. METHODS: This retrospective study combined cases from 4 equine referral hospitals. RESULTS: The stage of gestation at which uterine torsion occurred was a risk factor for survival of mare and foal. Overall mare survival was 53/63 (84%); when uterine torsion occurred at < 320 days gestation, 36/37 (97%) of mares survived compared to 17/26 (65%) survival rate when uterine torsion occurred at > or = 320 days gestation. Overall foal survival was 54% (29/54). When uterine torsion occurred at < 320 days gestation, 21/29 (72%) foals survived compared to 8/25 (32%) when uterine torsion occurred at > or = 320 days gestation. Thirty mares were discharged from the hospital carrying a viable fetus following uterine torsion correction and 25/30 (83%) of these mares delivered live foals that survived beyond the neonatal period. CONCLUSIONS: Prognosis for survival for mares and foals following uterine torsion is good and improves if torsion occurs < 320 days compared to > or = 320 days gestation. CLINICAL RELEVANCE: Gestational timing of uterine torsion should be considered when advising clients about the prognosis for survival of the mare and foal. The prognosis for a mare delivering a live foal is good if the mare is discharged from the hospital following uterine torsion correction with a viable fetus.     

Epidemiology of bovine anaplasmosis in dairy herds from Costa Rica

Bovine anaplasmosis is endemic and occurs in almost all areas of livestock production of Costa Rica. The aim of this study was to determine the seroprevalence and risk factors of anaplasmosis in dairy farms of Costa Rica by the recombinant truncated MSP-5 (rMSP-5) enzyme-linked immunosorbent assay (ELISA). Serum samples were obtained from 733 cattle from 20 commercial dairy herds of Costa Rica. The overall seroprevalence was 37.2% and herd seroprevalence ranged from 20.0 to 72.0%. The age-specific seroprevalence was 49.3% in young and 33.4% in adult animals. The main risk factors associated with seroprevalence were season of occurrence of clinical cases (rainy season) (OR=22.8), presence of tabanids (OR=9.5) and stable flies (OR=6.2), stable flies control measures (OR=3.2), non-use of ear tattoos (OR=2.8), interval of veterinary visit (≤ 60 days) (OR=2.7), altitude of the farms (<800 masl) (OR=2.6) and age (<2 years) (OR=1.8). The results indicated that exposure of cattle to Anaplasma marginale is common in dairy herds of Costa Rica and endemic instability situation probably is due to inadequate vector control.     

Obstetrical emergencies

This article discusses different techniques that can be used in the diagnosis and treatment of obstetrical emergencies. Female reproductive emergencies commonly encountered by small animal practitioners include pyometra, dystocia, cesarean section, mastitis, eclampsia, uterine torsion, and uterine prolapse. A thorough knowledge of normal and abnormal reproductive behavior will aid the emergency veterinarian in successfully managing such cases. Timely diagnosis and treatment of these emergencies will often give a good outcome.