Animal Science Department

 

Date of this Version

Fall 12-17-2010

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 Professors L. Aaron Stalker and Terry J. Klopfenstein. Lincoln, Nebraska: December, 2010
Copyright 2010 Sandra Villasanti

Abstract

A grazing study was conducted at the University of Nebraska Gudmundsen Sandhills Laboratory from mid-June to late-August across two years (2009 and 2010) to evaluate the effects of supplementation with mixtures of wet distillers grains (WDGS) and straw or hay on grazed forage intake. Twenty 1 ha paddocks replicated over two blocks were randomly assigned to one of four treatments: Control (CON) at the recommended stocking rate (1.68 AUM/ha in 2009 and 1.64 AUM/ha in 2010), and three double stocked treatments supplemented with 60% straw and 40% WDGS (STRAW), 60% hay and 40% WDGS (LOW), and 70% hay and 30% WDGS (HIGH). Forty yearling steers were stratified by BW and assigned randomly to treatment paddocks, giving a total of five steers per treatment. Five paddocks on each block were rotationally grazed for each treatment once during the experimental period. Post-grazing standing crop was determined by clipping five 0.25 m2 quadrats from each paddock at the end of the grazing period. Pre-graze forage allowance was calculated by adding an estimated amount of forage intake to the amount of forage remaining in the paddocks at the end of the grazing period. Forage intake was estimated by the difference between pre-graze and post-grazing forage availability. During the first year of the study, there was no difference in ADG between CON and HIGH; steers supplemented with 60:40 blends of straw or hay with WDGS presented higher ADG than the other two treatments. During the second year, steers in the STRAW treatment achieved significantly lower ADG than steers in the other treatments. Forage intake was significantly higher for the CON steers and intake of range forage was reduced by 18% to 22% when the animals were supplemented with the mixes. Mixing WDGS with low quality harvested forage to cattle grazing rangeland may be an alternative to increase or maintain stocking rates without hurting animal performance.

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