Research indicates that supplementing fat to young beef cows can improve pregnancy rates, according to Colorado State University Animal Scientist Patrick Burns. Results are particularly encouraging when the source of fat is fish meal high in omega-3 fatty acids.

Early embryonic mortality ranges from 16 to 42 percent, Dr. Burns says, and costs the US beef industry millions of dollars annually.

Fat supplementation for 65 days prior to calving has increased fertility rates in beef and dairy cows by 8 to 20 percent in research trials. Sources of fat have included plant oils such as from cotton seed, sunflower seed, safflower seed and soybeans, and animal sources and fish meal.

A trial comparing fish meal supplements with another protein source, corn gluten meal, demonstrated a positive effect on first-service conception rates for first-calf beef cows. Cows in the study received either corn gluten meal or fish meal beginning 25 days prior to breeding and continuing for 90 days. The group receiving fish meal had a first-service conception rate of 76 percent compared with 62 percent for those supplemented with corn gluten meal. Weights and body-condition scores remained similar between the two treatment groups, suggesting that both supplements met the animals' protein needs but fish meal had an added effect on fertility.

Dr. Burns concludes that feeding fat to young beef cows does improve pregnancy rates. Researchers, he says, still need to determine the optimal time to feed supplemental fat and identify which types of fat supplements provide the most consistent results.