Diseases of Concern: Diseases of Concern: BVD and BVD and Trichomoniasis Trichomoniasis Robert Mortimer, DVM Robert Mortimer, DVM Russell Daly, DVM Russell Daly, DVM Colorado State University Colorado State University South Dakota State University South Dakota State University
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Diseases of Concern:Diseases of Concern: BVD and BVD and TrichomoniasisTrichomoniasis
Robert Mortimer, DVMRobert Mortimer, DVMRussell Daly, DVMRussell Daly, DVM
Colorado State UniversityColorado State UniversitySouth Dakota State UniversitySouth Dakota State University
Host
EnvironmentAgent
Management
The Epidemiologic Triad The Epidemiologic Triad
TrichomoniasisTrichomoniasis
From 1987-1990 Had over 50 positive herds in Colorado
Primary Infection 90 days lostPrimary Infection 90 days lostSecondary Infection 30 days lostSecondary Infection 30 days lostReinfectionReinfection Rate 50%+ within 9 Rate 50%+ within 9
monthsmonths
Trichomoniasis: ECONOMICSIGNIFICANCE
Clark and Duffey. Aust. Vet J. 1983
Typical HistoryTypical History
• Pregnancy Rates may be decreased by10- 50%– Function of size of herd, length of breeding
season, time of pregnancy diagnosis• Increased losses of pregnancy• Usually with additional information it is
determined that the disease actually entered the herd a year ahead of owner concern for a problem
FETAL BVDV INFECTION FETAL BVDV INFECTION DURING GESTATIONDURING GESTATION
persistent infection
abortion, weak or stillbirth
infertility congenital defectsrepeat breeding
immune responsed 0 d 283d 125 d 150d 58 d 90
What about the bull?What about the bull?KNOWN:•PI possibility•Testes immunologically protected site•BVDV shed semen•Viral transmission andInfection can occur
Can this result in development of a PI calf? Rare! Single study, frozen semen from a known PI bull used in 12 susceptible heifers resulted in all being pregnant, all infected, and 1 of the 12 was a PI calf. Meyling and Jensen. Veterinary Microbiology 17: 97-105. 1988.
What does this mean relative to natural service???
Beef Cow HerdsBeef Cow Herds
• Many animals in same stage of reproductive cycle– especially stage of gestation
• Herd usually handled as a group
TAKE HOME MESSAGE!TAKE HOME MESSAGE!
• All herds should have monitoring/surveillance plan
• Plan should be put in place for monitoring herd additions
• In high risk herds, have a PI eradication plan
Beef Cattle - Prebreeding Test of Calves, Bulls, Cattle without Calves
Negative
Retain in Herd
Positive
Sell for Slaughter
Bulls and Cattle without
CalvesRemove Positive Calves and Dams
from Herd Prebreeding
Calves
Adapted from:Kelling,et al,The Bov Pract, 34:1 (2000) 13-22
Remove Positive Calves and Dams from Herd Prebreeding
Sell positive calves for slaughter
Test Dams
Positive Cow - PI calf product
of PI cow
Sell for slaughter
Only cow may return to herd
Negative Cow - PI calf from
acute infection
Adapted from:Kelling,et al,The Bov Pract, 34:1 (2000) 13-22
BVD VaccinationBVD Vaccination
• May be prevented with well planned vaccination program