Effects of Fescue Toxicosis Induced Heat Stress on Fetal ProgrammingMeghana SrinivasanAdvisor: Dr. Daniel W. Shike Mentor: Frank Ireland Stake Holders: Dr. Steve Cerny, Tom Saxe, and Terry Mefford

Introduction• Tall fescue: common grass used for livestock grazing found

on 35 mil acres in the US • Endophyte: fungus that lives between cells walls in grass • Types:

– Endophyte-Infected Tall Fescue: Kentucky-31• Drought resistant, sturdy against bugs• Toxic ergot alkaloids cause fescue toxicosis and decreased performance

– Endophyte free: Jesup• Not as sturdy • Increased health and performance

– Novel Endophyte-Infected Tall Fescue: Jesup Max Q • Persistent as KY-31• Comparable performance to endophyte free

http://forages.oregonstate.edu/tallfescuemonograph/seed_trade/novel_endophytes

Hypothesis• Summer Experimental Hypothesis:

– We hypothesis that cows grazing on KY-31 will show decreased performance compared to cows grazed on the novel endophyte-infected fescue (Jesup Max Q).

• Fetal Programming Hypothesis:– We hypothesize that cows grazed on KY-31 will calve

earlier, have calves with decreased birth weights, and have decreased immunoglobulin concentrations in their milk compared to cows grazed on novel endophyte-infected tall fescue.

Objectives• The objective of this summer’s study is to

observe and evaluate how grazing on novel endophyte-infected fescue vs. infected fescue will affect the pregnant cows.

• The overall objective of this study is to evaluate how the heat stress brought on by fescue toxicosis will effect fetal development.

Experimental Method• 8 groups of ten cows assigned to two treatment

groups• 4 groups will graze Jesup Max Q, a novel

endophyte-infected fescue (NE) for the entire summer

• 4 groups will graze Kentucky-31 (KY-31), an endophyte-infected the entire summer

• Each group will rotate pastures within their treatment every ten days

• Data will be collected at three assigned time points during trial period

Timeline for TestsTime Point

On Study

1 Expected calving

2

Date 5/28, 5/29

6/3 7/28,7/29

8/4-7 9/21 10/1, 10/2

10/6-9

Day 0,1 6 61, 62 68-72 87 97,98 102-105

Tests BCS, HCS, Bleed, BW(2)

RR BCS, HCS, Bleed, BW(2)

RR BCS, HCS, Bleed, BW(2)

RR

• Body Condition Score: Ranges 1-9 (very thin-obese)• Hair Coat Score: Ranges 1-5 (very fine sleek hair-rough, curly hair)• BW (2): Body Weight taken over a 2-day period • RR: Respiration Rate• Time Point 3 scheduled for after calving

ResultsAverage Body Weight (lbs.) KY-31 (E+) Jesup Max Q (NE)

On study (5/28/14) 1307 1281

Time Point 1 (7/29/14) 1442 1453

Change 135 173

Average Daily Gain 2.2 2.8

Average Hair Coat Scores KY-31 (E+) Jesup Max Q (NE)

On study (5/28/14) 2.3 2.0

Time Point 1 (7/29/14) 1.3 1.1

Change -1.0 -0.9

Results (cont.)Average Body Condition Scores KY-31 (E+) Jesup Max Q (NE)

On study (5/28/14) 5.4 5.8

Time Point 1 (7/29/14) 5.9 6.2

Change +0.5 +0.4

Average Respiration Rates (breaths per min)

KY-31 (E+) Jesup Max Q (NE)

On study (5/28/14) 46.0 43.8

Time Point (8/5/14) 48.2 43.3

Change +2.2 -0.5

Results (cont.) • Cows grazing NE had an increased body weight

gain compared to cows grazing E+ • 173 vs. 135 lbs.

• Overall cows exhibited similar HCS and BCS changes between treatments

• Respiration rates for E+ group did increase• Study is still in progress, further data must be

collected from the last time point• Significance of data is still unknown.

Still to be done…• All data for Time Point

3• Analyze all blood

samples for serum prolactin concentrations at the end of the study best indication of heat stress

• Collect birth weights and data on health and performance of calves

• Statistical analysis of data

Outcomes• Overall preliminary results for each of the

groups show noticeable differences in average daily gain

• Cows on Jesup Max Q had a 21% increase in ADG vs. KY-31

(contd.)• If calves born from cows grazing KY-31 are found to

have lower birth weights and performance, this would mean that the ergot alkaloids produced by endophyte-infected tall fescue do have a detrimental effect on fetal development.

• The results of this experiment could help answer the question of whether or not the consumption of endophyte-infected tall fescue had a detrimental effect on the performance of calves

Expected Deliverables• 10-pg. Research paper• Research poster• Presentations at:

– Explore ACES – Undergraduate Research Symposium,

or– American Society of Animal Science

Midwestern Meeting

Thank you!