Mammary gland biopsy does not affect colostrum yield of sows: a pilot study

As litter size has increased, the amount of colostrum ingested per piglet has decreased. Thus, increased colostrum yield of sows becomes more important in order to ensure that each piglet receives a sufficient amount. In this regard, biopsy of mammary gland tissue in sows for analyzing gene expression or RNA profiling may provide a tool for studying factors affecting colostrum yield. The aim of the study was to investigate whether mammary gland biopsy before parturition itself affects colostrum yield of the sow. A total of 12 multiparous sows (parity 2–7) were used for this experiment. Biopsies were performed in 8 sows three days before the expected farrowing date and the other sows (n = 4) served as controls. On the day of biopsy, sows were moved into individual crates and udders were disinfected three times with a povidone‐iodine (7.5% Betadine; Leiras, Helsinki, Finland) solution. With an automatic biopsy needle (14 gauge; 10 cm length, 22 mm penetration depth, Monopty 121410; Bard Oy, Finland), we took biopsies from the lateral‐caudal part of the 1st, 3rd, and 5th pairs of the mammary gland. Colostrum intake was assessed based on piglets’ bodyweight at birth and 24 h after birth. Data were analyzed by MIXED model. There was no difference in the colostrum yield between the biopsy group and the control group (n = 4; 4249.9 ± 711.2 vs. 3347.0 ± 1005.7 g; p = 0.5). In addition, colostrum yield of sows within the biopsy group did not differ from that of their previous parity (4249.9 ± 630.3 vs. 4697.3 ± 727.8 g; p = 0.7). Our experiment suggests that biopsy of porcine mammary gland before parturition does not affect colostrum yield. Thus, this method can be effectively used in studies on the effects of nutrition, environment, and other factors on mammary gland function.