اثر دو روش تدریجی و ناگهانی خشک‌کردن بر شاخص‌های بیانگر سلامت پستان در گاوهای با دوره خشکی کوتاه

This study was conducted to determine the influence of two intermittent (1wk) and abrupt drying off methods on udder health index of dairy cows with 30d dry period. Eighteen multiparous dairy cows were dried off approximately 4 wk prior to the expected calving time in a completely randomized design. For intermittent milk cessation treatment, cows were dried off in the following manner. Milk samples were collected from front and rear quarters at 7d to 3d prior to drying off, at drying off, 14d, 7d prior to calving, at calving, and 7d post calving. Milk yield at drying off day was recorded. Lacteal secretion samples were stored at -18Ċ and used for lactoferrin quantitation. Other samples were stored at 4Ċ for somatic cell count, total bacteria count and other milk components. The results indicated that, there were no differences in fat, protein and lactose percentages and milk pH between two drying off methods (P>0.05). However, there was a significant effect of drying off methods on lactoferrin concentration it was higher in dairy cows dried off by intermittent milk cessation, applied in 2 and 1 wk prior to calving time (P<0.01). Total bacteria count was not different in the two drying off methods. Milk total bacteria counts was higher in rear quarters compared to front quarters (P<0.05). Milk somatic cell counts were higher in cows dried off by abrupt milk cessation (P<0.05). There was a positive correlation between milk somatic cell counts and total bacterial counts (r = 0.352, P<0.01). No significant difference was observed in colostrum and milk lactoferrin concentration, somatic cell counts, fat, protein and lactose percentages, between rear and front quarters. With respect to higher lactoferrin concentration in cows dried off by intermittent milk cessation and due to antibacterial action of lactoferrin against mastitis pathogens, it seem that intermittent milk cessation treatment is preferred for cows given short dry period.