Calf Morbidity and Mortality in Dairy Farms in Debre Zeit and Its Environs, Ethiopla
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Date
2004-06
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AAU
Abstract
A longitudinal prospective observational study on calf morbidity and mortality in dairy faons
in Dcbre Zeit and its environs was conducted from October II, 2003 to April 8, 2004 with the
objective of describ ing incidence of calf morbidity and mortality, investigating potential risk
factors related to calf morbidity and mortality and identification ofsomc pathogens associated
with calf diarrhea. A total of236 cah'cs, 51 from three large dairy famls and a random sample
of 185 calves from market oriented smallholder dairy famls in Ocbre Zeit and its surrounding
were included in the study. Each calf was ind ividually identified and regu larly monitored for
clinical health problems up to an age of six months. Infomlation on different potential risk
factors were collected by personal observation during the regular visit to farms and from
questionnaire survey conducted during the study. Fecal samples were also collected from
diarrheic calves for laboratory examination to detect entropathogens involved.
The overall incidences of crude morbidity and crude mortality found in this study were 61.5%
and 18.0%, respectively. Disease conditions/syndromes that were diagnosed in calves
included diarrhea, p.neumonia, navel ill, joint ill, septicemic conditions, congenital problems
and other miscellaneous cases. The most frequent disease syndrome was calf diarrhea with the
incidence of 42.9% followed by pneumonia (4.9%). The incidence of calf diarrhea and crude
morbidity were apparently higher in large dairy farms than in the market o riented smallholder
farms. However, the mortality was higher in the latter.
A total of 20 potential risk factors were investigated for their association with the risk of
crude calf morbidity, crude calf mortality and calf diarrhea using Cox's proportional hazard
model. Age was the only factor thai was found significantly associated with risk of crude calf
mortality (HR= 0.04, P= 0.001). Older calves above three months age were at lower risk of
mortality than younger calves under three months of age. When weaned calves were
considered, weanin~ age and age at first colostrum feeding were additional risk factors.
Among the risk factors examined, those found significantly associated with the incidence of
crude morbidity were age of the calves. age at first colostrum ingestion and cleanness of the
calf house. Older calves were at lower risk of crude morbidity (HR=O.42, P = 0.001) than
younger calves. Higher risk of crude morbidity were observed in calves that ingested their
first colostrum meal later than 6 hours of age as compared with those that ingested before 6
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hours (HR = 2.24, P = 0.001). Sim ila rly calves housed at unclean house were at higher risk of
crude morbidity than those housed in clean house (HR = 1.75, P = 0.024).
Risk factors with sign ifica nt assoc iation to calf diarrhea were age, condition of birth and
cleanness of calf house. Older age was again associated with low ri sk of diarrhea as
compared with younger age (HR = 0.24, P = 0.000). Calves from prolonged labor or dystocia
(HR = 3.01, P = 0.002) and housed at unclean house (HR = 2.34, P = 0.011) were at greater
ri sk of diarrhea than those calves from !lonnal delivery and in c lean house, respectively.
Based on laboratory examination, Sa/monella and Cryptosporidium were detected from
diarrheic calves at ' rate of 2/55(3.6%) and 4/55(7.2%), respectively. The serotypes of
Salmonella identified were Salmonella Typhimurium and Salmol/ella Heidelberg both of
which were susceptible to commonly used antibiotics.
In conclusion, the incidence of calf morbidity and mortality found in this study were high and
could affect the productivity of the dairy famls through mainly decreasing the availability of
replacement stock. Among the management risk factors investigated, time of first colostrum
ingestion and cleanness of the calf house were found very important; incidentally, these two
aspects of calf management are easy for observation and carrying out appropriate
interventions. Implementation of good calf management in these areas could contribute in the
reduction of the -high calf disease problems seen in this study_ Salmollella and
Cryptosporidilln/ were found in diarrheic calves and these pathogens in addition to their role
in calf diarrhea, are potent zoonotics. Individuals particu larly very young, elderly and
immunocompromised, in contact with calves are al a potential risk of infection and therefore,
efforts should be mounted to avoid such risks.
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Keywords
Calf, Cryptosporidium. dairy fanns, diarrhea, incidence, longitudinal study, morbidity, mortality, ri sk factors, Salmonella