Animal Science Department

 

First Advisor

James C. MacDonald

Date of this Version

Fall 12-3-2021

Citation

Jakub, D.A. 2021. Management of late summer planted annual forages for grazing and the impacts of novel Sweet Bran Plus products on performance and carcass characteristics of beef finishing steers.

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 C. MacDonald. Lincoln, Nebraska: December, 2021

Copyright 2021 Devin Anthony Jakub

Abstract

Two separate grazing studies were conducted to evaluate: 1) the effects of rapeseed inclusion into late summer planted oats on the performance of growing steers during late fall and winter (Exp. 1) and 2) the effects of forage allocation on forage utilization and performance of steers grazing a late summer planted oat-rapeseed mix (Exp. 2). Variation in the corn wet milling process can result in negative effects on animal performance, nonetheless, there remains interest in further exploration and refinement of corn wet milling byproducts to achieve optimal byproduct compositions and cattle performance. Thus, another experiment was conducted to evaluate the effects of novel versions of Sweet Bran Plus on performance and carcass characteristics of beef finishing steers (Exp. 3). In Exp. 1, inclusion of rapeseed into late summer planted oats improved average daily gain for steers grazing during late fall and winter compared to steers grazing an oat monoculture. Rapeseed inclusion also resulted in a lower cost of gain because of greater average daily gain and a lower seed cost for rapeseed. In experiment 2, allocating forage twice weekly by strip grazing resulted in a greater gain per unit of land and a lower cost of gain than continuous grazing. Continuous grazing did result in greater average daily gain during the 71-day grazing season, but strip grazing offered more grazing days per hectare. Steers on treatment B in Exp. 3 tended to have a greater dry matter intake, but no differences were observed among treatments for average daily gain or feed efficiency. Feeding treatment C resulted in decreased marbling score and yield grade. Grazing a late summer planted brassica-oat mix in late fall does improve performance compared to an oat monoculture and better forage utilization can be achieved by strip grazing a mix compared to continuous grazing. Novel Sweet Bran Plus versions A and B offer the best combination of steer performance and quality grade when fed in steam flaked corn-based finishing diets.

Advisor: James C. MacDonald

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