Toxic plants and congenital calf disease

When calves are born deformed, weak or with other problems, veterinarians and their clients should also consider the dam’s exposure to toxic plants during pregnancy. Tony Knight, BVSc, MS, Colorado State University, says the following plants are known to cause congenital defects in calves and other livestock:

“Crooked calf disease”

This syndrome describes calves born with skeletal deformities and cleft palates and has been shown to be caused by:

  • Several species of lupine
  • Locoweeds (Oxytropis and Astragalus species)
  • Tree tobacco (Nicotiana glauca)
  • Poison hemlock (Conium maculatum)

Teratogens

Teratogens are substances that cross the placenta and affect normal fetal development.

  • Various members of the night-shade family are suspected (Solanum species)
  • False lupine or golden banner (Thermopsis species)
  • Mescal (Texas laurel) or Sophora species

“In all cases, it is critical that the pregnant cow consume the plants
over a period of days in the first tri-mester of pregnancy,” Knight explains. “Eaten later in pregnancy, the fetus will not be affected.”

Knight says the classic plant that will cause fetal deformity at a very specific time of gestation is western false hellebore (skunk cabbage), Veratrum californicum. “Pregnant sheep must eat the plant on the 13-14th days of pregnancy to produce lambs with a single eye in the middle of its head  —  a cyclops. Cows may also be affected if eating the Veratrum in very early pregnancy.”

Pine needles from the Ponderosa pine tree, and various cypress and junipers (Cupressus  and Juniperus species), and some other species of pine trees can cause abortions in cattle eating pine needles in late pregnancy. Pine needles may also be a cause for weak calves at birth that die soon afterward. Locoweed may also cause calves to be born weak and fail to thrive.

For more information, see A Guide to Plant Poisoning of Animals in North America. A.P.Knight. Available through Teton New Media Publisher (www.teton nm.com).


Osteopetrosis in calves

By Jerome Nietfeld, DVM, PhD

Recently we diagnosed osteopetrosis in an aborted Red Angus fetus. This is the third consecutive year in which we have identified osteopetrosis in a Red Angus fetus, with each of the three cases from a different herd. Osteopetrosis can be inherited in cattle, including the red and black Angus, Hereford, Simmental, and Dutch Holstein-Friesian breeds.

Osteopetrosis-like lesions have also been reported in calves infected in utero with bovine viral diarrhea (BVD) virus (for a more complete discussion of the two forms of osteopetrosis see Kansas Veterinary Quarterly, Spring 2006, volume 9, No. 2). In the Red Angus cases, the affected calves were negative for BVD virus and the pathologic changes in the skulls and long bones were typical of inherited osteopetrosis and different from those reported in BVD virus-infected calves with osteopetrosis-like lesions. After the second osteopetrosis case, the Red Angus Association implemented a program to identify affected calves.

They also contracted with a researcher to identify the mutation responsible for osteopetrosis and to develop a test to identify clinically normal carriers of the osteopetrosis mutation. Such a test will also allow identification of offspring of carrier cattle who do not carry the osteopetrosis mutation. It is estimated that tissues from approximately 10 calves with osteopetrosis will be required for identification of the defective gene.

If anyone suspects osteopetrosis in a Red Angus calf, please contact Larry Keenan of the Red Angus Association at 940-387-3502 or Larry@redangus.org. Alternately, you can contact Jerome Nietfeld at the Kansas State Veterinary Diagnostic Laboratory at 785- 532-4460 or nietfeld@vet.k-state.edu.

If you suspect osteopetrosis in other breeds, please contact Nietfeld.

This information was excerpted from the Kansas Veterinary Quarterly, Winter 2008. To see past issues, follow this link.