Crooked calf disease due to lupine toxicosis occurs during which gestational window?

• A. Early gestation (~40-70 days)
• B. Mid gestation (~100-120 days)
• C. Late gestation (~250 days)
• D. Postpartum

Answer: (A)

Lupine toxins cause crooked calf syndrome when exposure happens during early pregnancy, because this is when fetal skeletal development and limb formation are most sensitive to disruption from teratogens. The alkaloids interfere with neuromuscular signaling in the developing fetus, leading to reduced fetal movement and resulting in joint contractures, spinal curvature, and other skeletal deformities that give the calf a crooked appearance after birth. The critical window is roughly 40–70 days of gestation; after this period, the fetus is past the stage where these malformations are typically induced, and exposure later in gestation is less likely to produce the same syndrome. Postpartum exposure cannot affect the fetus.