Breeding Yearling Heifers

Kari Lewis

Last week I received a question on the guidelines for breeding yearling heifers, so I thought that would be a pertinent topic for today.  Given that this is the often the time for making that ‘final cut’ on the replacement heifers and fertility testing those bulls, here’s a few points to keep in mind when when heading into the breeding season:

Yearling heifers should be 55% to 60% of their
mature bodyweight at breeding.  Photo by Kari Lewis.

·         Choose heifers that were born in the first 45 days of the calving season.  These heifers will be the oldest and are most likely to already be cycling, plus their mothers calved in the early part of the calving season as well.

·         Choose heifers that were born unassisted and nursed without assistance. 

·         Choose heifers with a calm disposition, these will be your momma cows for hopefully the next 10 or 12 years. 

·         Consider the heifer’s size and if it fits your herd.  The heaviest heifers may represent big, high growth females that might be too big for your environment.  Small, slow growing females are not good replacement heifer candidates either. 

·         Remember that any heifers that were born twin to a bull have an extremely high chance of being infertile.  It’s best to cull them or have a vet palpate them before breeding. 

·         Lastly, replacement heifers should be structurally correct, long bodied and deep made with a nice spring of rib. 

So, what size should a heifer be at breeding?  The recommendation through the 1980’s was that heifers should be about 2/3 of their mature bodyweight at breeding.  However, more recent research out of Nebraska and Miles City has shown that heifers can be 55% to 60% of their mature bodyweight at breeding, and still have acceptable pregnancy rates and longevity, as long as they are on a positive plane of nutrition from before the breeding season through calving. 

Using the 55 to 60% of mature bodyweight recommendation, if heifers are from a cowherd with 1,300-pound mature cows, they should average around 750 pounds at breeding.  These heifers then need to be on a sound nutrition program where they continue gaining weight and developing condition through calving as a first calf heifer.