Date of Award:

4-2013

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Advisor/Chair:

Juan J Villalba

Abstract

Pastures have been typically dominated by monocultures, only allowing herbivores access to one food type with unbalanced nutrient content and in some instances with single plant secondary compounds (SCs), which can be toxic if ingested at high concentrations. By establishing diverse pastures animals can select from a variety of plants with different concentrations and types of nutrients and SCs. The objectives of my study were to (a) determine if the type of plant diversity - tall fescue with either tannin-containing sainfoin or saponin-containing alfalfa − affects cattle preferences for these forages, (b) evaluate how readily fall-born calves reach finish body condition on these grass-legume pastures, and (c) determine the effects of sainfoin/tall fescue versus alfalfa/tall fescue pasture on meat quality and consumer acceptance. Foraging behavior, body weight, and pasture biomass before and after grazing was monitored when cattle strip-grazed 3 replications of 2 treatments repeated for 2 years (from May through September 2010 and from June through September 2012). Animals were allowed a choice between tall fescue and sainfoin [SAN] or alfalfa [ALF]) applied randomly in strips (fescue, legume, or fescue-legume mixture). No differences in average daily gains (~ 1 Kg/day) were detected between the 2 groups of cattle. I used scan samples at 5-min intervals from 0730 to 0930 to record foraging behavior. Animals spent most of the time grazing legumes and scans on legumes increased from the beginning to the end of the study. Scans and assessments of pasture biomass removal revealed greater use of sainfoin than alfalfa, whereas cattle in the ALF treatment removed more fescue than cattle in the SAN treatment. The presence of tannins in sainfoin likely contributed to these effects. Beef carcasses were very lean (select or standard quality grade), with 4-6% mean fat content. There were no differences between treatments regarding meat color, oxidative stability, fatty acid analyses, or consumer acceptance. Only 2 volatiles (nonanoic and decanoic acids) were greater in meat from the ALF treatment. Thus, cattle offered choices reached finish body weight at pasture and incorporated fescue into their diets even when legumes were available. The type of legume influenced foraging behavior but this effect did not impact animal performance, meat quality, or consumer acceptance.

Share

COinS