Studies on swine production systems for large-scale husbandry, 1: Some discussions on appropriate weaning age of pigs from the view point of their immunity level
1999
Okanemasa, Y. (National Federation of Agricultural Cooperative Associations, Tsukuba, Ibaraki (Japan). Central Inst. for Feed and Livestock) | Yamaguchi, T. | Maekawa, T. | Ubagai, H.
Countermeasures to chronic disease, occurred in many swine housings, should be carefully studied, if intended to complete the rationalized swine production systems. As one of the effective countermeasures, a segregated early weaning system has been introduced to the swine husbandry, in which the weaning age of pig is a very important factor. In this paper, the authors discussed the appropriate weaning age of pig, measuring the periodical changes of gamma-immunoglobulin content in blood plasma of 10 head of SPF sows and 19 head of pigs produced from the above sows. IgG content of nursing pigs decreased with the age increasing, and the decreasing rate of IgG content became smaller with the age increasing (P0.01). For a seasonal effect, there was a tendency for the decreasing rate of IgG content in the season from winter to spring (P0.08). Furthermore, the decreasing rates of IgG content with the age of pigs were highly correlated to the diurnal range of temperature (r
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