Functional state of mammary gland of sows dried off by different techniques

Abstract

Sows were dried off by a traditional method (control &minus; C, restricted feeding before, during and after weaning) or by a modified one (experimental &minus; E, intensive feeding before, during and after weaning). On day 5&minus;6 after weaning of the 3<sup or 6^th litter, in the sows lactating for the period of 6 weeks (experiment I) or 4 weeks (experiment II), histomorphological and caryometric evaluation of mammary alveoli was carried out. The cellular infiltrations (plasmocytes, eosinophils, histiocytes and neutrophils) in the mammary gland showed no significant differences between groups dried off by different techniques. The alveolar epithelial cell DNA index (<i>DI</i>) and nucleus volume (<i>V_N</i>) were higher in sows lactating for 4 weeks than in those lactating for 6 weeks and in sows after 3<sup lactation than in those after 6<sup lactation. In experiment I, after weaning of the 3rd or 6th litter, absolute <i>DI</i> values in groups C and E were as follows: 2.092, 1.520, 1.409, 2.443, and <i>V_N</i> 42.679, 28.060, 38.064, 48.185. In experiment II, they were 2.072, 3.039, 2.890, 3.208, and <i>V_N</i> 52.274, 63.213, 57.980, 63.337, respectively. After weaning of the 3rd litter, the domination of group E compared to group C was found during 4-week lactation (<i>DI</i> &minus; <i>P</i> &le; 0.01, <i>V_N</i> &minus; <i>P</i> &le; 0.01). In 6-week lactation, more favourable conditions were obtained in group C compared to group E (<i>DI</i> &minus; <i>P</i> &le; 0.001, <i>V_N</i> &minus; <i>P</i> &le; 0.001). After weaning of the 6^th litter, in 4-week lactation, the domination of group E in relation to group C was insignificant: <i>DI</i> + 11.0%, <i>V_N</i> + 9.24%, and during 6-week lactation, it was statistically confirmed (<i>DI</i> &minus; <i>P</i> &le; 0.01, <i>V_N</i> &minus; <i>P</i> &le; 0.01). The results justify the need of intensive feeding during the weaning time in sows with longer lactation compared to those with the shorter one, with the performance period prolonged till the 6th reproduction cycle.