Bison Mortality Survey 1999-2000 Dr John Berezowski Western College of Veterinary Medicine Saskatoon, SK Canada
Part 1- Producer survey In 2000, PhD student Dr John Berezowski surveyed bison producers about their observations of disease in their bison herds. Although the information was producerderived and unconfirmed by laboratory diagnoses, the results of survey were sciencebased and statistically legitimate. Unfortunately, the work was never peer reviewed and published. It is presented here for information purposes only.
Questionnaire Responses Alberta 223 Saskatchewan 142 Manitoba 48 British Columbia 36 Ontario 16 Quebec 11 NWT 1 Total 477
Farms Bison Average Cows 357 11,472 32.2 Bulls 393 1,979 5.0 Bred heifers 309 4,319 14.0 2 year olds 300 6,351 21.2 Yearlings 325 8,585 26.4 Calves 415 12,498 30.1 Total 477 45,020 95.0
Bull to Cow Ratios Total females Average :1 bull to 8 females Max: 5 to 1 Min: 1 to 27 Cows Average: 1 bull to 9 cows Max: 2 to 1 Min: 1 to 29 Heifers Average:1 bull to 5.5 heifers Max: 5 to 1 Min : 1 to 33
Abortion Abortion rate 5.5/1000 exposed cows Farms reporting abortion 14.8% Probably under reported
Twinning Total Herd 5.1/1000 births Cows 5.4/1000 births Heifers 3.3/1000 births Farms with twins 12.0%
Abandoned Calves Total herd 6.6/1000 births Cows 5.0/1000 births Heifers 8.6/1000 births Farms with abandoned calves 14.6%
Calving Difficulty Total Herd 7.2/1000 births Cows 4.5/1000 births Heifers 14.2/1000 births Farms that had calving difficulty 15.8%
Calving Difficulty Outcome Total herd calf died 83.4% cow died 32.3% Cows calf died 81.4% cow died 46.5% Heifers calf died 85.7% cow died 21.4%
Prolapsed Uterus Total herd.96/1000 births Cows.67/1000 births Heifers 1.4/1000 births Farms with prolapsed uterus 1.12%
Calf Mortalities First 24 hrs of life Total herd 2.2% calf mortality Cows 1.7% calf mortality Heifers 3.7% calf mortality Herds reporting calf mortality 35.4%
Calving Percentage Percentage of cows that deliver live calves Total females 89.1% Min: 0% Max: 100% Cows 88.9% Heifers 89.8% Min: 0% Max: 100% Min: 0% Max: 100%
Calf Mortalities 1 day of age to weaning Before pasture turnout 0.84% On pasture 1.65% At weaning 0.33% Herds reporting calf mortalities 73.4%
Yearling and 2 Year Old Mortalities Yearling mortalities 1.7% Herds with mortalities 13.5% 2 year old mortalities 0.6% Herds with mortalities 9.0%
Adult Mortalities Cow mortalities 0.8% Herds with mortalities 19.3% Bull mortalities 1.7% Herds with mortalities 5.1%
Causes of Calf Mortality Unknown 63 Trauma 24 Calf scours 7 Abandoned 5 Predation 5 Dystocia 4 Pneumonia 4 Congenital defects 2 White muscle disease 2 Blackleg 1 MCF 1 Navel ill 1 Abomasal ulcer 1 Hardware 1
Causes of Yearling Mortality Unknown 24 Trauma 7 Drowning 1 Parasites 1 Pneumonia 1 Copper deficiency 1
Causes of 2 Year Old Mortality Unknown 16 Trauma 8 Dystocia 2 Pneumonia 1 Abomasal ulcer 1 Neoplasia 1
Causes of Cow Mortality Unknown 41 Trauma 16 Dystocia 9 Parasites 4 Hardware 3 Drowning 2 Blackleg 1 Polioencephalomalacia 1 Predation 1 Poaching 1 Pneumonia 1 MCF 1
Causes of Bull Mortality Unknown 5 Trauma 7 Blackleg 1 MCF 1 Neoplasia 1 Hit by car! 1
Have your bison ever had this disease? Pink eye 151 Pneumonia 53 Lice 45 Calf scours 41 Capture myopathy 31 Foot rot 25 Lungworm 22 White muscle 21 Grain overload 17 BVD 16 Blackleg 11 Liver fluke 12 MCF 8 Bloat 8 Red water 4 IBR 2
Handling Injuries Injuries Per 1000 Mortalities Per 1000 Case fatality rate % Bulls Cows 2 year olds Yearlings Calves 19.8 1.9 9.7 10.9 1.8 16.2 10.3 1.8 17.8 9.7 2.4 24.2 17.6 4.9 27.7
Part 2 - Pathology Lab Survey Laboratories contributing Alberta BC Minnesota North Dakota South Dakota Saskatchewan Total submissions 844
Adult bison lab submissions No diagnosis 36 MCF 22 Pneumonia 21 Enteritis 17 Trauma 15 Liver disease 15 Fatty liver 11 BVD 7 Copper deficiency 7 Hardware 7 Lungworm 7 Emaciaton/starvation 6 Abscesses 5 Abomasitis 4 Rumenitis 4 Kidney disease 4
Yearling bison lab submissions No diagnosis 20 Pneumonia 16 Emaciation/starvation 10 Trauma 8 MCF 5 Enteritis 5 Septicemia/meningitis 5 Capture myopathy 2 Copper deficiency 2 Lungworm 2 White muscle 1 Blackleg 1 Wooden tongue 1
Lab submissions 1 month to 1 year old No diagnosis 26 Pneumonia 23 Enteritis 14 Trauma 8 MCF 7 Coccidiosis 7 Septicemia/meningitis 5 Abomasal ulcers 3 Copper deficiency 2 BVD 2 Lungworm 2 Polio 2 Calf diphtheria 2 White muscle 1 Blackleg 1 Hemophilosis 1
Lab submissions bison calves No diagnosis 9 Enteritis 16 Septicemia/meningitis 9 Starvation/emaciation 7 Pneumonia 5 White muscle 5 Congenital defects 4 Capture myopathy 3 Dystocia 3 Abomasal ulcers 3 Navel ill 1 Copper deficiency 1
Productivity Each cow should produce a calf for sale Total cows in herd Minus open cows Minus abortions Minus calf mortalities Equals total number of calves for sale
Where are the losses? Abortions 87 Dead within 24 hrs 293 Dead before turnout 110 Dead on pasture 210 Dead at/after weaning 44 Failed to calve 1543 Total 2287 Total cows present at calving 15791 Percentage loss 14.5%
Where are the losses? Didn t calve 67.5% Dead in 24hrs 12.8% Dead on pasture 9.2% Dead before turnout 4.8% Abortion 3.8% Dead at/after weaning 1.9%
What should we do? Prevent disease/mortalities? Yes BUT mortalities account for only 32.5% of all losses of productivity Trauma is more important than disease Prevent reproductive losses? Yes BETTER BANG FOR YOU BUCK Poor reproductive performance accounts for 67.5% of all losses of productivity