April 2013 - AFMA

ies showed that weight loss had a negative
effect on either embryonic weight (Study 1)
or embryonic survival (Study 2).
The lack of effect on embryonic survival
in Study 1 could be due to the relative
low weight loss of sows, compared with
Study 2. This indicates that weight losses of
up to 11% probably do not influence embryonic
survival and eventually litter size in
second parity sows.
Piglet birth weight can, however, be affected.
The conclusion is that weight loss of
more than 11% negatively affected embryonic
survival and possibly embryonic weight,
and should be prevented.
Sow reproductive issues
Weight loss during lactation consists mainly
of losses of body fat, body protein and body
water. Of these three, body protein losses
have been reported to have the largest effect
on reproductive performance (Clowes et
al., 2003ab; Willis et al., 2003).
Therefore, in Study 2 back fat depth, as
a measure for fat loss, was measured. In addition,
loin muscle depth as a measure of
protein loss was measured. Although high
weight loss sows lost more weight than low
weight loss sows, back fat loss was similar at
4,6mm and 4,8mm respectively.
Loin muscle depth loss was 4,2mm higher
for high weight loss than for low weight loss
sows. These results indicate that weight loss
was more related to loin muscle depth loss
(r = 0,6; P