Predictors and impacts of colostrum consumption by 4Â h after birth in newborn beef calves

As a predictor for CC4, suckle reflex had the highest specificity (98%), whereas calving ease had the highest sensitivity (89%). Calves with a weak suckle reflex had 41.6 (95% CI: 7.4-787.5) times greater odds of failed CC4 compared to calves with a strong suckle reflex (P < 0.0001). Calves with failed CC4 had lower serum IgG (P = 0.01), had lower odds of acquiring optimal passive immunity (>24 g/L serum IgG; OR = 6.4, 95% CI: 1.2-34.4; P = 0.02), and higher odds of being treated (OR = 2.8, 95% CI: 1.1-7.4; P = 0.03) than those that succeeded. Measuring suckle reflex in combination with calving ease was a quick and easy method to assess newborn beef calf vigor. The value of this Beef Calf Vigor Assessment was further emphasized by the negative impacts of failed CC4 on transfer of passive immunity and pre-weaning health.