Early identification of neonates at risk: Traits of newborn piglets with respect to survival

Despite technological changes and improved management, piglet mortality rem ains a problem for both production and welfare. Most preweaning mortality o ccurs within the first 3 days after birth because of problems with adaptati on and development. Thus, the purpose of our study was to determine the phy siologic state of newborn pigs with respect to piglet survival. Data were c ollected from 1024 live-born piglets of 106 primiparous German Landrace sow s to analyze relationships between farrowing traits, early postnatal vitali ty and blood chemistry, including immunity of piglets at birth. Surviving p iglets were compared with those that died during the first 10 days of life. The survivors were significantly heavier at birth (P=0.001), were born ear lier in the birth order (P=0.04), reached the udder and took in first colos tral milk more quickly (P=0.001) and had a smaller drop in rectal temperatu re 1 h after birth (P=0.001) than dead. However, dead piglets had significa ntly higher blood levels of inorganic phosphorus (P=0.0001), calcium (P=0.0 4) and urea (P=0.05), but a lower concentration of alpha(2)-macroglobulin a nd lower lymphocyte proliferation indices in response to pokeweed mitogen ( P=0.05). Models fitted for discrimination between survivors and piglets tha t died included, in addition to birth weight and litter size, the foraging behavior of neonates (time from birth to first suckle) and their thermoregu latory capacity (rectal temperature 1 h after birth) in the first experimen tal. unit, as well as prenursing biochemical measures (inorganic phosphorus , calcium and glucose) in the second experimental unit. These ethophysiolog ical and biochemical traits of early postnatal vitality are important deter minants of maturity and development at birth. Hence, breeding programs and perinatal housing and feeding conditions should ensure a high physiological maturity to improve mortality rates of neonates. (C) 2000 by Elsevier Scie nce Inc.