See also plants poisonous to animals, Plants Poisonous To Animals. Crooked calf disease, characterized by joint contractures, torticollis, scoliosis or kyphosis, cleft palate, and combinations of these defects is seen in calves of in cows fed Lupinus laxiflorus , L caudatus , L sericeus , or L nootkatensis between days 40 and 70 of gestation. The quinolizidine alkaloid anagyrine is the teratogen. Ingestion of L formosus causes similar skeletal defects and cleft palate in cattle and goats; the teratogen is the alkaloid piperidine. Fetal development is at greatest risk when lupines are grazed early in plant growth or during seed formation. Conium maculatum (poison hemlock) causes contracture-type defects and occasionally cleft palate in calves, goats, sheep, and pigs. It may be a contributing factor in contracted tendons in foals. Both the plant and seed are toxic and teratogenic. Other plants suspected of causing similar defects in calves include Senecio , Cycadales , Blighia , Papaveraceae , Colchicum , Vinca spp , and Indigofera spicata and related plants. Ingestion of Nicotiana tabacum produces skeletal defects in pigs similar to those induced in cattle and pigs by Lupinus and Conium . Nicotiana glauca also induces contracture-type defects and cleft palate in cattle, sheep, and goats. Sudan grass ( Sorghum vulgare ) is incriminated as a cause of arthrogryposis in horses, and S sudanese may cause arthrogryposis in calves.
Epidemics of giantism with cyclopian defects occurred in bands of sheep in southcentral and southwestern Idaho while grazing Veratrum californicum (skunk cabbage) on certain alpine ranges in early pregnancy.
Locoweed poisoning by plants of the genera Oxytropis and Astragalus in all types of range livestock (most commonly cattle, sheep, and horses) resulted in various clinical signs such as emaciation, visual impairment, neurologic signs, habituation, abortion, and congenital defects. Locoweed produces musculoskeletal defects in calves and lambs, and hypoplastic testicles and enlarged seminal vesicles in rams. Swainsonia and locoweed poisoning in growing cattle have similarities to genetic mannosidosis in Angus cattle because the alkaloid indolizidine-1,2,8-triol is a potent and specific inhibitor of the hydrolytic enzyme α-mannosidase.
Viruses:
Certain prenatal viral infections are teratogenic in cattle, sheep, goats, pigs, dogs, and cats but have not been incriminated in defects in horses. Akabane virus (see Akabane Virus Infection) causes abortion, premature birth, and arthrogryposis and hydranencephaly in cattle, sheep, and goats. Cache Valley virus causes similar defects in sheep.
Bovine viral diarrhea virus may cause cerebellar dysplasia, brachygnathia, alopecia, ocular defects, internal hydrocephalus, dysmyelination, and impaired immunocompetence. Fetal bluetongue virus infection may cause hydranencephaly, porencephaly, and arthrogryposis in sheep, and abortion, stillbirths, arthrogryposis, campylognathia, prognathia, hydranencephaly, and "dummy calf " syndrome in cattle. Other orbiviruses such as epizootic hemorrhagic disease and Chuzan viruses may cause abortion, congenital defects, and neonatal losses similar to bluetongue virus.
Wesselsbron disease virus ( Wesselsbron Disease: Introduction) in South Africa is reported to cause primarily neurologic defects such as arthrogryposis, hydranencephaly, porencephaly, and cerebellar hypoplasia in ruminant fetuses.
Border disease ("hairy shaker" or "fuzzy" lambs, Border Disease ) virus infection is manifest by embryonic and fetal death and various congenital defects involving the nervous, skeletal, integumentary, endocrine, and immune systems. Defects include arthrogryposis, brachygnathia, hypomyelination (particularly of the spinal cord), depressed immune responsiveness, and birth of small, weak lambs with poor growth and viability. The defective myelinogenesis is partially reversible if the lamb survives.
Classical swine fever virus ( Classical Swine Fever: Introduction), a togavirus, is teratogenic in piglets and causes congenital tremors, demyelination, internal hydrocephalus, arthrogryposis, and cerebellar hypoplasia. Japanese B encephalitis virus infection may result in hydrocephalus, cerebellar hypoplasia, and spinal hypomyelinogenesis in piglets.
Natural and experimental infection of pregnant cats with feline panleukopenia virus ( Feline Panleukopenia: Introduction) causes cerebellar hypoplasia in neonatal kittens. Infection of pregnant ferrets in utero with feline panleukopenia virus also resulted in cerebellar hypoplasia.
Nutritional Factors:
Deficiency of one or more nutrients during pregnancy may result in congenital defects in the newborn. Severe deficiencies may interrupt pregnancy or result in weak or nonviable young. Iodine deficiency is endemic in certain areas and may cause goiter or cretinism in all species. Congenital musculoskeletal abnormalities such as forelimb contracture and ruptured common digital extensor tendon have been reported in foals with hypothyroidism. Copper deficiency causes enzootic ataxia in lambs; manganese deficiency causes limb deformities in calves. Vitamin D deficiency may cause neonatal rickets, and vitamin A deficiency may cause eye defects or harelip. Experimentally, teratogenic effects have been induced by deficiencies of choline, riboflavin, pantothenic acid, cobalamin, and folic acid, and by hypervitaminosis A.
Physical Agents:
Atresia of the gut, particularly the colon, may result from external pressure on the amnion during rectal palpation between days 35 and 40 of gestation. Torticollis, scoliosis, and frequently one or more defective limbs in foals have been associated with intrauterine fetal positioning, especially in caudal and transverse presentation. Pervious urachus in foals is reported to be associated with twisting of the umbilical cord.