|Abstract:||Three studies were carried out under typical farrowing house conditions to evaluate the effects of birth weight, drying, and oxygenation of piglets on rectal temperature in the early post-natal period. Studies 1 and 2 used completely randomized designs, with litter as the experimental unit, and piglet a sub-sample of litter; Study 3 used a generalized randomized block design, with piglet as the experimental unit, and litter the blocking factor. All piglets were weighed at birth and rectal temperatures were measured at 0, 15 (20 for Study 3), 30, 45, 60, 90, 120, 180, 240, and 1440 min after birth. Piglets were assigned to 1 of 3 Birth Weight Groups (BWG): Light (< 1.0 kg); Medium (1.0 to 1.5 kg); Heavy (< 1.5 kg). Data were analyzed using PROC MIXED of SAS and statistical models included fixed effects of treatment (Studies 2 and 3), BWG, time, and all interactions, and in Study 3, the random effect of replicate within litter.
Study 1 used 40 litters (420 piglets) and evaluated the effect of birth weight. Piglets in all BWG experienced a temperature decline after birth. Light piglets had lower (P < 0.05) temperatures than Medium and Heavy piglets at all times except at birth. Medium pigs had lower (P < 0.05) temperatures than Heavy pigs between 15 and 60 min but not subsequently (P > 0.05).
Study 2 used 26 litters (281 piglets) with 2 Piglet Drying Treatments: 1). Control (not dried); 2). Desiccant (dried at birth with a cellulose-based desiccant). There were Piglet Drying Treatment by BWG interactions (P < 0.05) at all times except at birth. From 15 to 240 min after birth, the Desiccant treatment had higher (P < 0.05) temperatures than the Control. Between 15 and 120 min, temperatures of Light pigs were lower (P < 0.05) than those in the other 2 BWG for Piglet Drying treatments. However, the temperature difference between the Light and other 2 BWG was considerably lower for the Desiccant than the Control treatment.
Study 3 used a total of 24 litters (270 piglets) with 3 Oxygen treatments: 1). Control [remained in farrowing pen] 2). Ambient Oxygen [piglets placed in a chamber at ambient oxygen for 20 min after birth] 3). 40% Oxygen [piglets placed in a chamber at 40% oxygen for 20 min after birth]. All piglets were dried at birth with a cellulose-based desiccant. Between 20 and 60 min, the Control had higher temperatures (P < 0.05) than the other treatments. There were Oxygen Treatment by BWG interactions (P < 0.05) between 20 and 90 min, but not (P > 0.05) at birth or subsequent times. There was no effect of Oxygen treatment (P > 0.05) for Heavy pigs between 20 and 60 min. However, Light and Medium pigs had higher (P < 0.05) temperatures on the Control than the other treatments between 20 and 60 min and 20 and 45 min, respectively.
In conclusion, piglets on all studies experienced a temperature decline within the first hour after birth. Subsequently, temperatures increased and approached temperature at birth by 24 h after birth. Piglets that were dried with a desiccant had higher temperatures than undried piglets from 15 to 240 min after birth. Placing piglets in an oxygen-rich chamber had no positive effect on post-natal body temperatures. Light piglets generally had lower temperatures than the other 2 birth weight groups on all treatments in all 3 studies.