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HIGH DEOXYNIVALENOL AND ERGOT ALKALOID LEVELS IN WHEAT GRAIN AND THEIR EFFECTS ON GROWTH PERFORMANCE, RUMEN PARAMETERS, AND HEALTH STATUS OF FEEDLOT CATTLE

Date

2023-09-28

Journal Title

Journal ISSN

Volume Title

Publisher

ORCID

0009-0006-1784-1377

Type

Thesis

Degree Level

Masters

Abstract

The objective of this study was to assess the impacts of a mixture of deoxynivalenol (DON) and ergot alkaloids (EA) in a wheat-based finishing diet on rumen function, blood parameters, incidence of liver abscesses, growth performance, and carcass traits of feedlot cattle. Forty Angus crossbred beef steers (450 ± 6.0 kg; 8 ruminally cannulated) were blocked by body weight and randomly, allocated to 1 of 4 treatments; control-low (CON-L; 0 mg/kg), control-high (CON-H: 0 mg/kg), mycotoxin-low (MYC-L; 5.0 mg/kg DON, 2.1 mg/kg EA), and mycotoxin-high (MYC-H: 10 mg/kg DON, 4.1 mg/kg EA) and housed in individual pens over a 112 d finishing trial. Wheat screenings were added to the CON diets to ensure a chemical composition profile that was like the mycotoxin diets (CON-L had 31% and CON-H had 63% of the diet as wheat screenings on a DM basis). Diets (DM basis) consisted of 83% wheat-based concentrate, 12% barley silage, and 5% supplement. Ruminal and blood samples were collected at the beginning of the trial, and every 28 days thereafter, and ruminal pH was measured for 7 d using indwelling loggers by inserting a week before sampling for each period. Data collected was analyzed using SAS software. Total volatile fatty acid concentration was lower (P = 0.03) for MYC steers as compared to CON steers. The CON steers experienced a longer duration with ruminal pH < 5.2 as compared to MYC steers, as well as higher (P < 0.001) AUC (pH × min and pH × min/kg DM) for both pH <6.0 and <5.6. Platelet count was lower for MYC steers (P < 0.001), as were liver parameters including alanine aminotransferase (ALT), globulin, and blood urea nitrogen concentration (P ≤ 0.008); whereas the A:G (albumin:globulin ratio) was higher (P < 0.001) when compared to CON steers. Lymphocyte count and glutathione peroxidase activity (GPx) were elevated (P ≤ 0.003) in MYC steers when compared to CON steers. Intake of DM, starch, CP, NDF, and ADF were lower (P < 0.001) for MYC steers compared to the CON steers. Despite a lower intake, DM, crude protein (CP), and starch digestibility were higher (P ≤ 0.002) in MYC steers when compared to CON steers. Final body weight, ADG, G:F, and NEg were lower (P < 0.001) for MYC steers than CON steers. Hot carcass weight and backfat thickness were also lower (P < 0.001) in MYC steers, but saleable and lean meat yield were greater (P ≤ 0.007) compared to CON steers. The incidence of liver abscesses was not affected by the inclusion of mycotoxins in the diet. Results suggest that a mixture of mycotoxins impacted the immune status, growth performance, and carcass traits of feedlot steers, even at limits currently deemed safe (MYC-L) by the Canadian Food Inspection Agency (CFIA). Therefore, CFIA guidelines may require further review to include additional recommendations for mycotoxin mixtures, particularly when a mixture of DON and EA is present in the diet.

Description

Keywords

deoxynivalenol, ergot alkaloids, beef cattle, wheat grain

Citation

Degree

Master of Science (M.Sc.)

Department

Animal and Poultry Science

Program

Animal Science

Part Of

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DOI

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