Ask a Nutritionist: Corn Byproduct's Impact on Conception Rates

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Reader Question:

This question concerns the feeding of corn by-products and its effect on recip cows becoming pregnant with embryos. Cows were fed alfalfa/grass hay free choice with 12 lbs. dry corn gluten per day. Hay was early bloom and of very good quality. Our conception results went from 60-70% to 40-45% this year. Previous years haylage and cracked corn had been fed.

Will this level of gluten have adverse effects on conception rates? If so what would be maximum to feed? Our goal was to have cows in optimum condition for fertilization. Your help is greatly appreciated for both AI and ET.

Nutritionist Response from Dan Larson:

There is a definite link between overfeeding protein and reduced conception rate.  However, the exact number is difficult to pinpoint and is likely different for each group of cows. 

As a general rule of thumb, it should be safe to keep total ration protein under 14%, whereas the total ration protein in your system was 17% or greater.  Excess protein (nitrogen) is processed by the body through the urea system, which is excreted in the urine.  However, excess nitrogen will exist as ammonia in the blood, which increases acidity of the blood, and consequently, of the uterus.  Thus, even though you may have fertilized embryos, they will die prior to implantation, resulting in low conception rate. 

The root of your problem is not the dry gluten, per se, rather is a result of the entire ration.  Dry gluten will work well to increase body condition, however, keep total ration protein in mind when formulating for next year.

-Dan Larson is a ruminant nutritionist at Great Plains Livestock Consulting, Inc. His experience in both cow–calf and feedlot cattle operations offers a unique perspective on the beef industry.