Effects of barley processing and variety on ruminal disappearance in feedlot cattle

Open Access
Shampoe, Kelsey Virginia
Area of Honors:
Animal Sciences
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Tara Louise Felix, Thesis Supervisor
  • William Burton Staniar, Honors Advisor
  • barley
  • cattle
  • feedlot
  • hulless
  • in situ
  • rumen
  • digestibility
Although common in animal feeds, traditional varieties of barley have a tough outer hull that necessitates processing and increases cost. Using hulless varieties increases digestibility of barley in nonruminant diets; however, data on the efficacy of these varieties as feed for cattle are lacking. Therefore, objectives of this study were to compare ruminal disappearance of dry matter (DM), neutral detergent fiber (NDF), and starch in traditional whole barley (WB), rolled barley (RB), and whole hulless barley (HB). Ruminally fistulated steers (n=8) were used. Each treatment, WB, RB, and HB, was ground in a Wiley mill with no screen to mimic the mastication that would occur if the animals were fed naturally. Then, samples were weighed into Dacron bags and incubated in the rumen for 3, 6, 12, 24, 48, and 72 hours. Residual contents were analyzed to determine in situ disappearance of DM, NDF, and starch. Data were analyzed using MIXED procedures of SAS (9.4 SAS Inst., Cary, NC) with repeated measures. Steer was the experimental unit and significance was declared at P<0.05. Dry matter disappearance (DMD) was greatest (P<0.05) for RB at all time points and did not differ (P>0.05) between HB and WB between hours 3 to 12. However, HB had greater (P<0.05) DMD from 24 to72 hours than WB. The NDF disappearance (NDFD) was greatest (P<0.05) for HB at all time points, while RB and WB were comparable. Despite a 50% increase in starch degradation of HB compared to WB at hour 3, the 2 varieties did not differ (P>0.05) until hour 72, likely because of steer variation. In situ NDFD was increased in HB when compared to RB and WB; however, DMD and starch disappearance were not markedly different.