The health of 3081 heifer calves born in 122 dairy herds in the south-west of Sweden
from 1 January to 31 December, 1998, was monitored from birth until 90 days of age.
The calves were kept either in individual pens (n=2167), in group pens, with 3-8 calves
to a pen and manual feeding of milk (n=440), in group pens with 6-30 calves per pen
and an automatic milk-feeding system (n=431), or with their dams (n=43). Disease incidence
was recorded by farmers and project veterinarians, who clinically examined the calves
and auscultated their lungs every 2-3 months. A disease was graded as 'severe' if
the general loss of condition or of appetite in the calf continued for >2 days or
if the animal suffered severe weight loss due to the disease. The effects of season,
breed, housing, and type of colostrum feeding, and time, place and supervision of
calving on the incidences of diarrhea, severe diarrhea, respiratory disease, other
infectious disease and moderately to severely increased respiratory sounds, were analyzed
by logistic-regression models (with herd as a random effect). The total morbidity
rate was 0.081 cases per calf-month at risk. Incidence rates of arthritis, diarrhea,
omphalophlebitis, respiratory disease and ringworm were 0.002, 0.035, 0.005, 0.025
and 0.009 cases per calf-months at risk, respectively. The odds ratios for diarrhea
and severe diarrhea were increased in Swedish Red and Whites (OR: 1.6, 2.3) and in
calves that received colostrum from first-lactation cows (OR: 1.3-1.8), and for severe
diarrhea in calves born in summer or that received colostrum through suckling (OR:
1.7, 1.8). The odds ratios for respiratory disease and increased respiratory sounds
were increased in calves housed in large-group pens with an automatic milk-feeding
system (OR: 2.2, 2.8). Supervision of calving was associated with a decreased odds
ratio for respiratory disease (OR: 0.7) and birth in individual maternity pen or tie
stalls with a decreased odds ratio for increased respiratory sounds (OR: 0.5-0.6).
Cross-breeds with beef breeds were associated with increased odds ratios for increased
respiratory sounds (OR: 2.1-4.3) and colostrum from second-lactation cows and birth
during night for other infectious disease (OR: 1.6, 1.5).