Technical note: machine milking of sows--lactational milk yield and litter weights.

This study was designed to 1) determine milk yield of sows that were machine milked; 2) assess the effects of pulsation rate, pulsation ratio, and pig removal on milk yield; and 3) assess litter weights. In Exp. 1, four sows were milked daily to 60 d postpartum. There were differences (P <.05) in milk yield among sows, the greatest being 1,898 mL/d. Daily milk yield peaked between 15 and 25 d postpartum. Litter weights were 18.0 ± 1.0 kg at farrowing and 60.8 ± 12.1 kg at d 60. In Exp. 2, four sows were milked daily for 28 d. Pulsation rate and ratio (150/min and 28:72, milk:rest, and 60/min and 50:50) were alternated on a daily basis and pigs were isolated for either 0 or 60 min before milking. The higher pulsation rate resulted in more milk per milking (202 ± 13 vs 168 ± 13 mL; P <.05). Pig removal resulted in 221 ± 11 vs 148 ± 14 mL milk ( P < .01). Pig removal times and pulsation characteristics affect the amount of milk obtained, but milk removal from sows has a severe effect on litter weight. This system can be used to harvest sow's milk for pharmaceutical purposes, but supplementation of the pigs is necessary.