H. Everts et Ra. Dekker, BALANCE TRIALS AND COMPARATIVE SLAUGHTERING IN BREEDING SOWS - DESCRIPTION OF TECHNIQUES AND OBSERVED ACCURACY, Livestock production science, 37(3), 1994, pp. 339-352
Balance trials and comparative slaughtering with breeding sows were us
ed to calculate the standard deviation (sd) of the retention and to ca
lculate the contribution of the different error sources to the total v
ariance of retention within a method. During pregnancy and lactation b
alance trials (nitrogen, carbon, energy, calcium, magnesium and phosph
orus) were performed with 60 sows. In lactating sows the retention in
the litter was calculated from the chemical analysis of weaned piglets
. For the comparative slaughter technique 12 sows were slaughtered at
first mating (live weight 125 kg) as a reference, 14 sows at the end o
f first pregnancy and 23 sows after the third lactation. In the course
of the experiment 11 sows were culled. The sd of retention in the lac
tation balance trials was much higher than in pregnancy trials. The ma
in source of variance for nitrogen and Ca retention was the intake and
for Mg and P retention the faecal excretion and for carbon and energy
retention the gaseous exchange. With comparative slaughter the sd of
fat and energy retention was affected by the estimate of body composit
ion at the start of the experiment. The sd of nitrogen and mineral ret
ention was mainly associated with the sampling procedure and analysis
of the carcass. From the results it can be concluded that the balance
technique resulted in a smaller ad of retention than the comparative s
laughter technique when retention is measured over a limited period (<
3 months).