We see a lot of variation in cattle, even when we utilize full siblings within sire groups. We wonder why there is so much variation from the lightest calf to the heaviest calf, and from the highest-quality grade to the lowest-quality grade, and from the calf that stays in the herd until she is 14 to 17 years old versus the one that falls out at 2 years old.

Size especially matters when it comes to needle selection as you treat or vaccinate calves. Needles that are the incorrect length or diameter can cause serious issues.