Session: Ruminant Nutrition I: Feed Additives

289 - Phytogenic Feed Additives as a Potential Strategy to Mitigate the Negative Effects of Heat Stress in Growing Heifers

Thursday, July 15, 2021

9:30 AM – 9:45 AM EST

Location: Kentucky International Convention Center (KICC), L005/009

Presenting Author(s)

Shelby M. Ramirez

Regional Research Manager
BIOMIN America Inc.
Overland Park, Kansas

PDF Slides and Audio

Author(s)

JW

Janaka Wickramasinghe

Department of Animal Science, Iowa State University
Ames, Iowa
NS

Nadiia Stepanchenko

Department of Animal Science, Iowa State University
Ames, Iowa
MO

Maria Oconitrillo

Department of Animal Science, Iowa State University
Ames, Iowa
JS

Jayamuni Silva

Department of Animal Science, Iowa State University
Ames, Iowa
BG

Brady M. Goetz

Graduate Research Assistant
Department of Animal Science, Iowa State University
Ames, Iowa
MA

Megan A. Abeyta

Graduate Research Assistant
Department of Animal Science, Iowa State University
Ames, Iowa
RM

Raj Murugesan

Biomin
Overland Park, Kansas
AT

Antonia Tacconia

BIOMIN Holding GmbH
Getzersdorf, Niederosterreich
LB

Lance H. Baumgard, PhD

Professor
Iowa State University
Ames, Iowa
RA

Ranga Appuhamy

Department of Animal Science, Iowa State University
Ames, Iowa

Phytogenic feed additives that contain anti-inflammatory and antioxidant properties may have potential to reduce inflammation and oxidation observed during bouts of heat stress. The trial objective was to determine the effects of a phytogenic feed additive on markers of stress in heifers subjected to diurnal heat stress (dHS). Eighteen Holstein and four Jersey heifers (5-6 months of age; d1 BW=205±9 kg) were assigned to two dietary treatments (n = 11) based on breed and age; 1) a basal TMR diet (CTL), 2) CTL supplemented with 0.25 g/head/d of a proprietary blend of phytogenics (PFA; BIOMIN America, Inc., Overland Park, KS). Heifers were housed individually and fed their respective treatments for 14d prior to dHS (d-14-1), subjected dHS (d1-7), and followed through a recovery period (d8-11). Weights were collected at d1 (baseline), d7 (end of dHS), and d11 (end of recovery). The temperature set point was assigned at 33°C from 0900 to 2100 h and allowed to equilibrate with outside temperature during night (24°C) for a total of 7d dHS. Total DMI (tDMI) and DMI from 0900 to 2100 h (hsDMI) were recorded daily. Serum was collected at d1, 2, 7 and 11 to determine effect of treatment on markers of oxidation, inflammation, and stress. Treatment effects were analyzed using PROC MIXED in SAS with treatment and time as fixed effects and heifer as a random effect. Temperature humidity index during dHS was greater during the day (84.5) versus night (73.3). There were no treatment differences (P>0.05) in d 0–11 on ADG, ADFI, or GF between treatments. However, PFA numerically increased hsDMI, reduced (P< 0.05) haptoglobin and tended to reduce (P< 0.10) lipopolysaccharide binding protein compared with CTL. Overall, dietary PFA may be a potential strategy to mitigate the stresses that heifers experience during dHS.