|
This study was conducted to investigate the effects of castration and ovariectomy on growth performance and plasma hormone concentration in pigs. A total of 48 pigs of 35 days of age were used. The results obtained in the present study are summarized as follows: 1. No significant difference was found in average daily gain between ovariectomy group (898.6g) and control gilt group (862.7g), and between castration group (926.0g) and control boar group (945.5g), respectively. Average daily gain of control boar group, however, was significantly higher than that of control gilt group (p<0.05). There was no significant difference in feed/gain between ovariectomy and control gilt group and between castration and control boar group, respectively. Backfat thickness was significantly (p<0.05) higher in ovariectomy or castration group than in control gilt or boar group, respectively. 2. Plasma concentration of IGF-I was significantly (p<0.05) increased during the period of 5 weeks of age (45.1 pm0.72 ng/ml) to 15 weeks of age (356.3pm3.05 ng/ml), and maintained constantly afterwards in control gilt group, as was in control boar group. That of ICF-I tended to be lower in ovariectomy or castration group than in control gilt or boar group, respectively. Regarding steroid hormones of estradiol-17beta, progesterone, and testosterone, the concentration was extremely low at 5 weeks of age, however, increased from 11 weeks to 23 weeks of age in control gilt or boar group, while it was nearly under detection limit in ovariectomy or castration group. 3. Chemical compositions of pork loins were not affected by ovariectomy or castration, except that crude ash content was significantly (p<0.05) higher in castration group than in control boar group. These results indicated that ovariectomy or castration had no effects on growth performance and feed utilization. However, the concentration of sex steroid hormones was under detection limit in ovariectomy and castration group. Further studies, however, are needed to develope the techniques which minimize the stress related with castration or ovariectomy for the production of high quality pork.
|