I'd guess that of the generally used beef breeds, Charloais and Simmental have the highest yearling (1 year) weights. However, in the beef business, bigger is not always better. The larger breeds will often require more feed and take longer to "finish" in the feedlot, sometimes produce a carcass that's too large to fit the consumer's requirements, and sell for less than a smaller animal. You might check out the "Breeds" link here at Cattle Today; it will tell you mature sizes of various breeds. Good luck...
Which types of beef cattle have
> the highest weights at maturity
> and, what are thier average
> weights? What breeds of cattle
> have the best steer weights at 1
> year old?
Any of the Continental breeds, Limousin, Charolais, Simental, etc. will have the largest weights at 12 monthes of age. Are you just concerned with weight? Most cattle are not harvested at 12 months of age, they are usually harvested at 16-18 months of age and again these same breeds will have the highest finished weights.