Colostrum intake and neonatal characteristics in piglets experiencing varying lengths of expulsion phase

The objective of this study was to investigate how the cumulative expulsion interval, litter size, and birth order influence the characteristics of newborn piglets from hyperprolific sows, as well as their intake of colostrum. Analysis was conducted on the temporal aspects of parturition in 254 sows, including 3920 piglets. Newborn piglet characteristics examined encompassed delivery time, birth order, birth status, umbilical cord rupture, meconium staining, delivery ease, birth weight, blood oxygen saturation, and heart rate. From the raw data, colostrum intake, birth interval, and cumulative birth interval of each piglet were computed. Piglets were sorted based on the cumulative expulsion interval into nine categories: 0-30, 31-60, 61-90, 91-120, 121-150, 151-180, 181-210, 211-240, and >240 min. Litter sizes were categorized into three groups: 10-13, 14-17, and ≥18 piglets per litter. The birth-order ranking referred to the piglet's position within a litter and was categorized into four quartiles: 1, 2, 3, and 4. On average, the expulsion interval, cumulative expulsion interval, and colostrum consumption were 14.8 ± 21.8 min, 138.6 ± 155.7 min, and 407.6 ± 162.1 g, respectively. In litters with ≥18 piglets, the percentage of piglets with inadequate colostrum intake (<300 g) was higher compared to litters with 10-13 piglets (33.1 % vs. 12.9 %, P < 0.001) and 14-17 piglets (23.9 %, P < 0.001). The occurrence of stillbirths in the fourth quartile of the litter was higher than in the first (16.0 % vs. 2.2 %, P < 0.001), second (4.0 %, P < 0.001), and third (7.8 %, P < 0.001) quartiles. Among litters with ≥18 piglets, those born in the third quartile exhibited lower colostrum consumption compared to those born in the first quartile (346.0 ± 9.9 vs. 391.4 ± 8.6 g, P = 0.028). Colostrum intake decreased with longer cumulative expulsion intervals, evident from a notable decline starting at 90 min post-farrowing compared to piglets born within the first 30 min (P = 0.004). Interestingly, colostrum consumption exhibited a negative correlation with the cumulative expulsion interval (P < 0.001), but not with individual piglet expulsion intervals (P = 0.460). Piglets born with meconium staining were most prevalent among those with a cumulative expulsion interval of >240 min. In summary, both the cumulative expulsion interval and birth-order ranking significantly impact the physiological characteristics of newborn piglets and their colostrum intake. Colostrum consumption decreases and newborn piglet characteristics change with higher cumulative expulsion intervals. Identifying piglets at high risk of hypoxia and implementing appropriate treatments and management strategies within an optimal timeframe could aid pig producers in reducing pre-weaning mortality among piglets born to hyperprolific sows.