Herd performance vs. Pathogen presence in Nevadas Bighorn Herds - - PowerPoint PPT Presentation

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May 20, 2023 218 likes •503 views

Herd performance vs. Pathogen presence in Nevadas Bighorn Herds Mike Cox Peregrine Wolff, DVM Nevada Department of Wildlife Epizootic pneumonia of bighorn sheep or an all age, die-off Polymicrobial pneumonia that is initiated by

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Herd performance vs. Pathogen presence in Nevada’s Bighorn Herds

Mike Cox Peregrine Wolff, DVM Nevada Department of Wildlife

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Epizootic pneumonia of bighorn sheep

an all age, die-off

Polymicrobial pneumonia

that is initiated by infection with the bacteria Mycoplasma ovipneumoniae

r
M. ovi

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Bacteria that live in the back of the throat move down to the lungs causing pneumonia

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4 outcomes for our sheep herds

Only herds where we have:

Samples from the die-off
Pre and post herd performance data

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First outcome

All age, die-off with complete loss of herd

Hays Canyon -2007

Speculative: Jarbidge – 1981 Tobins- early ‘90s

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Second outcome

All age die-off with a 1-2 years of poor lamb recruitment then bounce back

Fairview –Slate 2007

Speculative: Ruby Mountains - 1997 East Humboldt – 1997 Mormons - 1981

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Third outcome

All age die-off with a 1-20 years of poor or variable lamb recruitment and no bounce back

Santa Rosa range – 2004 East Humboldt’s – 2009 Ruby Mountains - 2009 Snowstorms – 2011 Pancakes – 2011 White Pine/Duckwater Hill-2011 Pilot/Leppy Hills - 2010 Speculative: Sheep Range - 1986 Egans – 2008

Mt. Moriah - 1991

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Fourth outcome

Some deaths but very minor negative herd response

Lone Mountain Gabbs Valley Silver Peaks Monte Cristo Range Speculative: River Mountains Eldorados McCulloughs Spring Range

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Outcome for herds unknown

Bare Mtn. Stonewall NTTR Montanas East Humboldt – Rocky Mountain Bighorn Sheep River Mountains Eldorados McCullough Mtn. Spring Range

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Why Variable Outcomes?

Pathogen related

Chronic Carriers
Strain type

Herd Density Nutrition Genetics Other Environmental factors

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5-20% of survivors may still carry the bacteria

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Similar to many pathogens, there are multiple strains of M. ovi which gives us a clue as to the origin of the infection

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Southern Nevada Strain Mojave Strain

11/ 11/ 2013 2013

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Southern Nevada Strain Mojave Strain

11/ 11/ 2015 2015

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0.0 0.0 10.0 10.0 20.0 20.0 30.0 30.0 40.0 40.0 50.0 50.0 60.0 60.0 50 50 100 100 150 150 200 200 250 250 300 300 350 350 400 400 1996 1996 1999 1999 2002 2002 2005 2005 2008 2008 2011 2011 2014 2014

Lam amb Rat atio io Herd rd P Populat atio ion Estim imat ate

Fa Fairv irview/Sla late/Sand S d Sprin prings/Monte Cris risto, , Unit it 1 181

Lamb Ratio Population Estimate

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0. 0.0 10. 10.0 20. 20.0 30. 30.0 40. 40.0 50. 50.0 60. 60.0 70. 70.0 50 50 100 100 150 150 200 200 250 250 300 300 350 350 400 400 450 450 500 500 1975 1975 1978 1978 1981 1981 1984 1984 1987 1987 1990 1990 1993 1993 1996 1996 1999 1999 2002 2002 2005 2005 2008 2008 2011 2011 2014 2014

Lamb Ratio tio Herd Popula latio ion Estim imate te

Mor Mormo mon Mount Mountains ns, U Uni nit 2 t 271

Lamb Ratios Population Estimate

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0. 0.0 10. 10.0 20. 20.0 30. 30.0 40. 40.0 50. 50.0 60. 60.0 70. 70.0 80. 80.0 50 50 100 100 150 150 200 200 250 250 300 300 350 350 400 400 450 450 500 500 1981 1981 1984 1984 1987 1987 1990 1990 1993 1993 1996 1996 1999 1999 2002 2002 2005 2005 2008 2008 2011 2011 2014 2014

Lam amb Rat atio io Herd rd P Populat atio ion Estim imat ate

McCu cCullough Ran Range, U Unit 263 263

Lamb Ratios Population Estimate

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

50 100 150 200 250 300 350 400

1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 Lamb Ratio Herd Population Estimate

River Mountains, Unit 269

Lamb Ratios Population Estimate Survey Total

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 50 100 150 200 250 300 350

1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 Lamb Ratio Herd Population Estimate

Spring Mountains, Unit 262

Lamb Ratios Population Estimate

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 100 200 300 400 500 600 700

1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014 Lamb Ratio Herd Population Estimate

Gabbs Valley/Gillis Ranges, Unit 205 and 207

Lamb Ratios Population Estimate

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100 200 300 400 500 600 700

1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 Lamb Ratio Herd Population Estimate

Monte Cristo Range, Unit 213

Lamb Ratios Population Estimate

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 50 100 150 200 250 300 350

1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 Lamb Ratio Herd Population Estimate

Santa Rosa Range, Unit 051

Lamb Ratios Population Estimate

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0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 50 100 150 200 250 300 350

1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 2015 Lamb Ratio Herd Population Estimate

Pancake Range, Unit 134

Lamb Ratios Population Estimate