Abstract:
The application of the surgical castration in different ages in different farms under Sri
Lankan conditions was identified as a serious welfare problem and the study was
conducted to evaluate the effects of four selected ages on welfare of young piglets by
observing their behaviours and to suggest a suitable age among them for Sri Lankan
conditions. The experiment was conducted in NLDB Pig Breeding Unit at Walisara.
The four ages checked were, 1. Surgical castration on day 7 of birth, 2. Surgical
castration on day 14 of birth, 3. Surgical castration on day 21 of birth 4. Surgical
castration on day 28 of birth. For each treatment three replicates were used.
Twelve Duroc pregnant sows having more than 75% Duroc blood from three different
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parities, gilt, 4 parity and 5 parity were selected for the experiment and were
assigned to separate pens. Just after each farrowing the litter was notched, birth weights
were recorded and a programme schedule was prepared. Each litter was weighed in
every 7 days interval up to weaning (0-42 d) in individual basis. According to the
treatment, in a pre-determined day, the surgical castration and sham castration were
applied to randomly selected male animals. Just after the castration the observations
were started and continued for three consecutive days following castration. The
observations were taken every 5 minutes intervals for 3 hours in the morning and 2
hours in the afternoon according to the ethogram. At the same time the position of the
piglets in the pen was also observed and was recorded in every 15 minutes intervals.
After the observation period (on third day of castration) each litter was weighed.
The observations (Sleeping, sleeping postures, position in the pen and pain related
behaviours, lying - without sleeping behaviour and suckling behaviour) were analyzed
using SAS version 6.12 computer package. The castration and sham castration had no
significant effect on sleeping behaviour, sleeping postures, position in the pen or pain
related behaviours in all four ages of castration. But just after castration in treatment 1,
pigs have shown the highest sleeping behaviour and pigs in treatment 4 have shown the
least. The least lateral recumbency posture at sleeping has observed in treatment 4 and
the highest in treatment 1. In treatment 2 (surgical castration on day 14 of birth) the
average behaviours (LE/SL, LR/SL) of both castrated and sham castrated male pigs
were mostly the same. Also just after surgical castration they have stayed at the comers
more frequently. Surgical castration on day 7 after birth has given the least pain related
behaviours (shivering, rapid respiration) for young male pigs than other ages. But
considering the suckling behaviour just after castration, the castrated males in treatment
2 (castration on day 14 of birth) had shown the highest suckling behaviour over sham
castrated males than other treatments.
This study concludes that surgical castration on day 7 after birth has given the least pain
related behaviours at the surgical procedure but in economic aspects, castration on day
14 of birth is the best, because suckling is important for the growth and the
development of immune system. For Sri Lankan conditions can suggest surgical
castration on day 7 after birth considering only the welfare aspects of young male pigs
and considering both economic and welfare aspects can suggest the treatment 2
(surgical castration on day 14 of birth). Surgical castration on younger ages was found
to be more suitable than older ages of young male pigs.