Use of kernza intermediate wheatgrass straw on beef cows and dairy heifer diets

Authors: PIZARRO, DANTE - University Of Wisconsin; Akins, Matthew; CROOKS, ARIN - University Of Wisconsin; WATTIAUX, MICHEL - University Of Wisconsin; PICASSO, VALENTIN - University Of Wisconsin

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/2024
Publication Date: 11/12/2024
Citation: Pizarro, D., Akins, M.S., Crooks, A., Wattiaux, M., Picasso, V. 2024. Use of kernza intermediate wheatgrass straw on beef cows and dairy heifer diets. ASA-CSSA-SSSA Annual Meeting Abstracts. November 10-13, 2024.

Interpretive Summary:

Technical Abstract: Kernza intermediate wheatgrass is a novel dual-use perennial grain and forage crop with environmental and economic benefits for farmers. Kernza straw can be baled after grain harvest and used as forage. Beef cows and dairy heifers require low-energy and high-fiber diets. Thus, straw is commonly included in their diets to reduce energy density and increase diet fill to avoid over-conditioning. No information on animal performance fed Kernza straw is yet available. Therefore, two experiments were conducted to evaluate the performance of beef cows and dairy heifers fed Kernza straw in Wisconsin. In the first experiment, 36 pregnant Angus cows in a randomized complete design with 3 replications were fed two diets: 100% grass-alfalfa haylage, and 50% Kernza straw - 50% grass-alfalfa haylage over two years. In the second experiment, 24 pregnant Holstein heifers in a randomized complete design with 8 replications were fed three diets containing either 0%, 20%, or 40% of Kernza straw. Kernza straw reduced dry matter intake (-9.45%), change in bodyweight (-48.9%), and average daily gain (-49.1%) of beef cows when included in 50% in their diet. However, cows fed Kernza straw maintained their body condition without impacting calf birth and weaning weights. Inclusion of 20% and 40% of Kernza straw reduced dry matter intake of dairy heifers by 9.60 and 10.4%, respectively. However, heifers maintained their body condition with average daily gains of 0.98 kg/d, considered in the optimal range for replacement dairy heifers. Kernza straw as an alternative low-opportunity cost feed represents an option for beef and dairy producers to improve resource use efficiency while promoting a circular economy.