Escape protein for beef cows: I. Source and level in corn plant diets

Area of Science:

• Animal Science
• Ruminant Nutrition
• Beef Cattle Production

Background:

• Mature beef cows require adequate protein supplementation, especially during gestation and lactation.
• Corn-based diets are common, but protein sources can vary in efficacy.
• Slowly degraded protein sources are being evaluated for improved nutrient utilization.

Purpose of the Study:

• To evaluate the efficacy of dehydrated alfalfa meal (DEHY) as a slowly degraded protein source in corn-based diets for gestating and lactating beef cows.
• To compare DEHY with soybean meal (SBM) and urea as nitrogen supplements.
• To assess the impact of different protein sources on weight gain and performance.

Main Methods:

• Four trials were conducted: two winter grazing trials for gestating cows and two drylot trials for lactating cows.
• Diets included cornstalks, ground corncobs, and corn silage, supplemented with DEHY, SBM, or urea.
• Supplementation levels and diet compositions (crude protein equivalent - CPE, total digestible nutrients - TDN) were standardized.
• Cow weight changes were monitored to evaluate treatment effects.

Main Results:

• Gestating cows fed high DEHY gained more weight than those fed low DEHY or urea in one trial, but no differences were found in the second gestating trial.
• Lactating cows fed DEHY gained more weight than those fed urea in one trial, but gains were similar to SBM.
• Cow weight gains in the second lactating trial were not affected by the type of protein supplementation.

Conclusions:

• Dehydrated alfalfa meal (DEHY) may offer benefits as a protein supplement for gestating and lactating beef cows, but results can be variable.
• Soybean meal (SBM) and urea also serve as effective nitrogen sources, with performance depending on trial conditions and diet composition.
• Further research may be needed to optimize the use of DEHY and other slowly degraded protein sources in beef cattle diets.