Teagasc (Agriculture and Food Development Authority), Ireland
Abstract
peer-reviewedThe objective of this study was to compare the effects of rearing calves outdoors, with
and without all-weather calf jackets, with calves reared indoors on calf immunity and
animal performance. In February 1999, male Holstein calves (mean (s.e.) weight 55
(1.90) kg) were randomly assigned to one of three treatments (n=30 per treatment): 1)
outdoors with jacket, (J; mean age 19 (s.e. 2.0) days); 2) outdoors without jacket (NJ;
mean age 19 (s.e. 1.8) days), and 3) indoors on straw (I; mean age 19 (s.e. 1.0) days).
Calves received an individual allowance of 25 kg of milk replacer dry matter during the
first 42 days with ad libitum access to a concentrate ration from day 0 to 63. The jackets
were removed from the calves on day 42. Live-weight gain from day 0 to day 63 of
the study was not significantly different between treatments (J, 0.79; NJ, 0.80; I, 0.80
kg). Sixty percent of the J calves and 53% of the NJ calves required four or more antibiotic
treatments for respiratory disease while corresponding treatments were
required for 97% of the I calves. The incidence of diarrhoea was significantly higher in
both outdoor treatments compared to the I treatment. There was no significant difference
in white blood cell counts or in serum immunoglobulin concentrations between
treatments on days 0, 21, 42 and 63 or in in vitro interferon-γ production on day 63. It
is concluded that using calf jackets on calves reared outdoors had no beneficial effect
on calf performance or immune status. The incidence of respiratory disease was higher
and diarrhoea incidence was lower in calves reared indoors compared with calves
reared outdoors. There was no significant difference in incidences of diarrhoea and
respiratory disease between the two outdoor treatments
