Nursing behaviour, milk intake and growth rate in piglets

Milk production in 5 single-housed Yorkshire sows was measured using the isotope dilution technique with D2O as a marker. Sows were in their third parity and litter size was 7-13 piglets. Piglets were enriched twice, at 4-5 (period 1) and at 16-18 (period 2) days of age. During the measurement periods nursing behaviour of sows with litters were recorded using a time lapse video. Piglet teat order was recorded by direct observation. The individual milk intake was significantly correlated with piglet LW (+), piglet growth (+) and teat pair number (-). Teat pair number was also correlated with piglet LW and growth (both negatively), but not with piglet birth weight. No significant correlations between sow milk yield and nursing frequency or length of nursing bouts were found. Nursing frequency decreased from period 1 to period 2 (30.5 and 26.3 per day, P<0.01), as did the median length of nursing bouts (7.7 and 4.7 minutes, NS). Milk production per sow and day increased from 9.6 kg in period 1 to 14.0 kg in period 2 (P<0.05). The individual milk intake increased from 0.93 kg per piglet and day in period 1 to 1.40 kg in period 2 (P<0.05). Daily milk intake decreased by 0.059 kg (P<0.01) and piglet growth rate by 0.016 kg per day (P<0.01) with teat pair number. The conversion of milk into growth increased from 3.8 kg per kg in period 1 to 4.8 in period 2 (P<0.05). Thus, the data confirm the superiority of anterior teats over posterior teats regarding milk yield and piglet growth rate. In spite of a 14% decrease in nursing frequency from period 1 to period 2 (mean piglet age 6 and 19 days), milk yield in sows increased by 46%