Epidemiological investigations of an outbreak of intestinal atresia in two Israeli dairy herds

Bovine congenital defects recorded by veterinary practitioners

A mobile phone app was used by 59 veterinary practitioners to collect case histories and images of 191 cattle with congenital defects distributed nationally over a 3-year period. The majority of cases were recorded during the spring calving season (57.6%) in pluriparous dairy dams. The majority of calves were recorded at birth or within the first week (66.5%) in singletons born at full-term. On the majority of farms (75.9%), this was the only congenitally deformed bovine recorded up to that point in the year and on the majority of farms, there were no congenitally deformed cattle recorded in the previous 5 years. The majority of congenital defects (83.5%) were recorded in the musculoskeletal or digestive systems. The three most commonly recorded individual defects were intestinal atresia (24.1%), schistosomus reflexus (20.4%) and ankylosis (6.8%); multiple defects were recorded in 13.1% of cases. These findings highlight the relatively high prevalence of intestinal atresia and schistosomus reflexus in calves attended by veterinary practitioners, which warrants implementation of preventive measures. The project highlights the potential benefits of veterinary-practitioner apps to detect changing trends in endemic, or the emergence of novel, congenital or other conditions.

Risk factors for, and genetic association with, intestinal atresia in dairy calves

Intestinal atresia is an under-diagnosed congenital defect in cattle. It results in complete occlusion of the intestinal lumen and, unless surgically corrected, results in death or euthanasia of the affected calf. There is limited information on the incidence of this condition or on risk factors, including predisposing alleles, associated with the defect. In this study, active surveillance of 39 dairy farms over 8 years identified 197 cases of intestinal atresia among 56 454 calves born, an incidence of 0.35%. The majority of cases (83%) had occlusion of the jejunum, although cases with blockage of the colon (14%) or anus (4%) were also identified. The defect was twice as common in male as in female calves (p < 0.0001), and was more common in progeny of older cows than in progeny of first or second lactation cows (p < 0.001). Year and farm of birth were also significantly associated with incidence (p < 0.05). The incidence of intestinal atresia was highest among the progeny of three related Jersey sires, suggesting that a gene for intestinal atresia was segregating within this family. Linkage analysis utilising 28 affected progeny of two half-sib putative carrier sires identified two putative quantitative trait loci associated with the defect, on chromosomes 14 and 26, although no clear candidate genes were identified. There was no evidence of a sire-effect among the progeny of Holstein-Friesian sires. However, a case-control genome-wide association study involving 91 cases and 375 healthy controls, identified 31 SNP in 18 loci as associated with the defect in this breed. These data suggest that intestinal atresia in dairy calves is not a simple Mendelian trait as previously reported but a complex multigenic disorder.

Comparison between allantochorion membrane and amniotic sac detection by per rectal palpation for pregnancy diagnosis on pregnancy loss, calving rates, and abnormalities in newborn calves

The objectives of the present investigation were to evaluate the pregnancy diagnosis by detection of either the allantochorion membrane (FMS) or amniotic sac (ASP) by per rectum palpation (PRP) during late embryonic or early fetal period on pregnancy loss (PRL) at reexamination, calving rates, and abnormalities in newborn calves. A controlled randomized blind design with 800 lactating dairy pregnant cows diagnosed by transrectal ultrasonography (TRUS) between Days 35 and 57 of gestation from one dairy farm were included. The cows were randomly divided according to detection of allantochorion membrane (FMS group; n = 264), detection of amniotic sac (ASP group; n = 266), and TRUS (control [CON] group; n = 270). TRUS was considered as the criterion standard method of comparison. The entire PRP was performed by one experienced veterinarian. Then, all the cows were reexamined only by TRUS between 2 and 4 weeks later by two independent veterinarians to assess PRL. The calving rate one (number of cows calved divided by the number of cows initially pregnant) and calving rate two (number of cows calved divided by the number of cows pregnant at reexamination) for each group was calculated. All abortions and stillborns were necropsied, and calves alive were followed for 5 days. The overall initial PRL (between initial pregnant cows and reexamination) for FMS, ASP, and CON groups was 7.4% (19/258), 8.8% (23/262), and 9.2% (24/260), respectively (P = 0.75). The overall late PRL (between reexamination and calving) for FMS, ASP, and CON groups was 4.2% (9/213), 5.7% (12/209), and 4.2% (9/216), respectively (P = 0.71). The calving rate one for FMS, ASP, and TRUS groups was 79.1% (204/258), 75.2% (197/262), and 79.6% (207/260), respectively (P = 0.63). The calving rate two for the same groups was 85.4% (204/239), 82.4% (197/239), and 87.7% (207/236), respectively (P = 0.27). The number of fetuses aborted late, premature, and mature dead from FMS, ASP, and CON groups was 6, 4, and 5, respectively (P = 0.85), and no abnormalities at necropsy were detected. One stillborn male calf with atresia coli after 281 days of gestation from a cow examined by ASP at Day 51 was diagnosed. It was concluded that the use of either FMS or ASP for pregnancy diagnosis during late embryonic or early fetal period did not increase the PRL, affect calving rates, or produce calves with congenital abnormalities.

Effect of early pregnancy diagnosis by per rectum amniotic sac palpation on pregnancy loss, calving rates, and abnormalities in newborn dairy calves

The objectives of the present study were to evaluate the effect of per rectal amniotic sac palpation (ASP) for pregnancy diagnosis during the late embryonic period on pregnancy loss, calving rates, and abnormalities in newborn calves. A controlled, randomized, blocked, blind experiment containing 680 lactating pregnant dairy cows with a viable embryo diagnosed by transrectal ultrasonography was performed. Two dairy operation sites (farm A and farm B) were selected. At each farm, the cows were randomly divided into control (CON) and ASP groups. The CON group was not subjected to pregnancy diagnosis via per rectum palpation. The ASP examinations were performed by one experienced veterinarian between Days 34 and 45 after breeding. All cows were reevaluated by transrectal ultrasonography only between 2 and 4 weeks later. Two calving rates were calculated: calving rate 1 (cows that calved from the initial number of pregnant cows) and calving rate 2 (cows that calved from cows pregnant at reexamination). In farm A, the percentages of early pregnancy loss were 11.5% (19 of 165) and 13.2% (24 of 182) for the CON and the ASP groups, respectively (P = 0.64). In farm B, the percentage of early pregnancy loss was 11.2% (19 of 170) for the CON group and 8.8% (14 of 159; P = 0.48) for the ASP group. In farm A, the percentage of late pregnancy loss was 7.6% (11 of 145) for the CON group and 5.5% (8 of 155; P = 0.39) for the ASP group. In farm B, the percentage of late pregnancy loss was 3.7% (5 of 137) for the CON group and 6.3% (8 of 127; P = 0.32) for the ASP group. In farm A, early pregnancy loss was higher than late pregnancy loss (12.4% vs. 6.3%; P = 0.01), and in farm B, the same tendency was detected (10.0% vs. 4.9%, for early and late pregnancy loss, respectively; P = 0.02). In farm A, calving rate 1 was 81.2% (134 of 165) for the CON group and 80.8% (147 of 182; P = 0.92) for the ASP group. Calving rate 2 for the same groups was 92.4% (134 of 145) and 94.8% (147 of 155), respectively (P = 0.68). In farm B, calving rate 1 was 77.7% (132 of 170) for the CON group and 74.8% (119 of 159; P = 0.55) for the ASP group. Calving rates 2 for the same groups were 87.4% (132 of 151) and 82.1% (119 of 145), respectively (P = 0.20). Two female calves with atresia coli were diagnosed only in the CON group. It was concluded that ASP during the late embryonic period for pregnancy diagnosis did not increase the pregnancy loss, affect calving rates, or produce abnormalities in calves.

Modified colostomy technique for colonic atresia in calves

OBJECTIVE

To report a modified colostomy technique for permanent fecal diversion in calves with colonic atresia.

STUDY DESIGN

Prospective study.

ANIMALS

Calves (n=19) with colonic atresia.

METHODS

Clinical findings, white blood cell counts, radiologic, ultrasonographic, and intraoperative findings were recorded. Calves were randomly divided into 2 groups: group 1 (n=9) had conventional colostomy and group 2 (n=10) had a modified colostomy. Technique efficacy was evaluated by postoperative observation, owner satisfaction, and calf survival.

RESULTS

Fifteen (79%) calves were discharged from the hospital; 4 (21%) group 1 calves died within 24 hours after surgery. Two (40%) group 1 calves died 18 and 30 days after surgery and 5 (50%) group 2 calves died 2-60 days after surgery. Eight calves reached slaughter weight (120+/-10 kg); 5 group 2 calves grew normally but the 3 group 1 calves had lower weight gain. Owners of the calves with conventional colostomy reported that the evacuation of feces was continuous whereas owners of calves with the modified colostomy reported that feces were released through the stoma in intervals.

CONCLUSION

Modification of conventional colostomy by forming an hourglass shaped stoma lessens fecal incontinence but there was no difference in survival rate.

CLINICAL RELEVANCE

Modified colostomy was considered advantageous because of intermittent fecal discharge from the stoma compared with continuous fecal release in conventional colostomy. The modified technique seemingly has a beneficial effect on growth of the calf.

Surgical repair and management of congenital intestinal atresia in 68 calves

OBJECTIVE

To determine outcome and survival rate after surgical treatment of intestinal atresia, gender predilection, and effect of rectal palpation on the cause of atresia coli in calves. STUDY DESIGN; Prospective clinical study.

ANIMALS

Newborn calves (n=68).

METHODS

Data collected were husbandry system, anamneses, physical examination findings, surgical treatments, and postoperative results. Calves with atresia ani, and with atresia coli et recti had anal reconstruction and right flank colostomy, respectively. In midflank colostomized calves, the inner muscular layers were dissected to form a valve-like stoma.

RESULTS

Of 68 calves with intestinal atresia, 37 were treated surgically. Anal reconstruction was performed in 21 calves with atresia ani with a long-term survival rate of at least 6 months with good condition. Colostomy was performed in 14 calves with atresia coli and 1 with atresia coli et recti; survival rate was 73%. The case morbidity rate for intestinal atresia was 13.8% and for atresia coli, 5.7% in the hospital population. No gender predilection for occurrence of atresia ani and atresia coli was identified. Palpation per rectum for early pregnancy diagnosis did not predispose to atresia coli.

CONCLUSION

Surgical treatment of atresia ani through circular anal skin removal has a good prognosis for survival. Colostomy is not an acceptable treatment from the calf's perspective because of the resulting poor condition but the high survival rate is important to allow continued milk production of the dam.

CLINICAL RELEVANCE

Early diagnosis, supportive treatment, and surgical correction are important in management of atresia coli.

Surgery of the bovine large intestine

Cecal dilatation in cows and large intestinal atresia in neonatal calves are the most important diseases of the bovine large intestine amenable to surgical correction under field conditions. Clinical symptoms, diagnostic steps, surgical and medical treatment, etiopathogenesis, and prognosis are discussed. Surgery for correction of cecal dilatation, with and without retroflexion or torsion, can be performed under field conditions. In contrast, only anal reconstruction after atresia ani or colostomy in the case of atresia coli are amenable to field surgery; more complicated bypass procedures with anastomosis for atresia coli are best performed in hospital settings. Correcting intestinal atresia is not recommended because of animal welfare and breeding hygiene issues; it should be undertaken for salvage purposes only.

Surgical diseases of the small intestine

Surgical disorders of the gastrointestinal tract of cattle occur occasionally, and veterinarians are challenged to determine an accurate diagnosis and treatment for these conditions. Although surgical diseases most commonly occur in the forestomachs (dislocated abomasum, reticuloperitonitis) and the colons (cecal dilatation), this article focuses on lesions in the small intestine (duodenum, jejunum, ileum).