I would suggest some proven embryo matings.The better the cow the better the calf. I have a nice set of basically maternal bred females that wean heavy calves. I have rented a top bull from Phil Lautner for over ten years and have had bulls such as MAB clone,Heatwave clone,Jackpot, Dakota Gold clone and Milkman for 3 years.Havent had one cripple and each year have sold several calves of witch one of the top ones pays the lease.They love the colored up ones to show but not at the salebarn