Forages and Technology Management in Growing and Finishing Beef Cattle Systems

Authors

Kelton Adair, University of Nebraska-LincolnFollow

First Advisor

James MacDonald

Second Advisor

Travis Mulliniks

Third Advisor

Andrea Watson

Date of this Version

12-2023

Document Type

Article

Citation

Adair, K. C. 2023. Forages and Technology Management in Growing and Finishing Beef Cattle Systems. M. S. Thesis. Univ. of Nebraska, Lincoln.

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Animal Science, Under the Supervision of Professor James MacDonald. Lincoln, Nebraska: December 2022

Copyright © 2022 Kelton Cole Adair

Abstract

A systems study evaluated the effects of an implant [25.7 mg estradiol (Compudose; Elanco Animal Health)] at two rates of gain (LOW: 0.45 kg/d and HIGH: 0.9 kg/d) applied during the winter backgrounding phase in drylot and winter grazing systems and its effects on subsequent phases of production. HIGH supplementation with an implant during the winter backgrounding phase in the drylot system yielded the greatest ending body weight (EBW) during the summer backgrounding phase (P = 0.04). LOW supplementation, without an implant, improved summer backgrounding average daily gain (ADG; P = 0.05) while achieving similar carcass adjusted final body weight and hot carcass weight (HCW) as those wintered at HIGH with an implant. In the dormant meadow winter backgrounding system, additional supplement yielded increased winter and summer EBW and ADG (PP > 0.16).

A feedlot study compared the effects of a direct-fed microbial feed additive to no feed additive on performance and liver abscess rates in finishing beef cattle. The DFM technology used in this study was developed to reduce the abundance of Fusobacterium necrophorum and Streptococcus bovis in the rumen. Feeding this specific DFM at 1 billion bacterial cells/steer daily to finishing beef cattle did not significantly affect performance, carcass characteristics, liver abscess rate, or the severity of liver abscesses.

Rumen undegradable protein (RUP) values of crested wheatgrass (CWG) have not been well established. Knowing the amount of RUP available to cattle grazing CWG throughout the grazing season can help producers calculate MP supply and aid supplementation decisions throughout the grazing period. An experiment evaluated the forage value of crested wheatgrass harvested from Western Nebraska over a two-year period (2019-2020). The study found that crude protein decreased throughout the growing season while RUP % CP increased. The RUP content of CWG may range from 0.8% to as high as 1.21% of DM throughout the grazing season. RUP digestibility is less than 50% of RUP resulting in digestible RUP being less than 0.5% of DM.

Advisor: James MacDonald