There are a ton of studies out there to show that breeding heifer to calve by the time they are two is the most productive thing to do with your herd, but you also have to manage those heifers a little different until they are three.
Here is a quote from a fact sheet at
http://www.omafra.gov.on.ca/english/liv ... 91-067.htm
"Producers should aim to calve their replacement heifers by two years of age. This practice will improve the profitability of the beef operation by offsetting the high costs of feed, labour and investment in raising replacements. To produce the maximum pounds of calves in her lifetime, a cow must calve each year starting as a two-year-old. Research from Oklahoma shows that this is indeed true-heifers calving at two years of age produced an extra 330 pounds of calf on a lifetime basis over heifers calving at three years of age."
Here is another one that specifically states that breeding to calf at two will give the heifer a longer, more productive life:
http://www.dpi.vic.gov.au/agriculture/b ... rst-mating
"Well-managed
heifers calving first at two years have a higher lifetime productivity than heifers calving first at older ages. Although some producers believe that heifers calving at two years will have retarded growth and a subsequent reduction in productivity, a number of long-term experiments have shown that this is not the case."
The important thing here is that these young bred heifers need extra attention. If you do not intend to do that, then you will be better off waiting. People who buy bred heifers off of us want a heifer that is AI bred and bred to calve by the time she is two. The prevailing thought is that she is not fertile if she does not calf by two, there must be something wrong with her. We feed them better hay, and watch that they are getting to the hay ring (now that this is winter!). We AI to calving ease Simmental bulls, and look closely at EPD's on both the heifer and the bull we plan on using. We even used a calving ease Simmental bull (Beef Maker) on an Angus heifer (14 months old). She calved right before her second birthday with a 45 pound heifer calf! A little small for my taste, but the important part to remember is she had an easy birth, is doing a fantastic job raising that heifer, and has been bred back for next year (she has not passed over yet, we just completed our breeding for fall last week). She was the only two year old that we calved out, and was the last one to come into heat after calving, so she needed a little extra time to adjust but is doing just fine.
That is just us, raising Simm influenced cattle, but it seems to work well over here :tiphat:
