BEHAVIORAL AND PHYSIOLOGICAL-RESPONSES OF MEISHAN, YORKSHIRE AND CROSSBRED GILTS TO CONVENTIONAL AND TURN-AROUND GESTATION STALLS

A 5-wk study involving 48 bred gilts was conducted to evaluate behavio ral and physiological responses of four geneotypes (Meishan = MM, York shire = YY and crossbred (sire/dam = MY and YM) to two types of gestat ion stalls (conventional and turn-around). The behavior of gilts was v ideo-recorded on days 0, 7, 21, and 35. Blood samples were taken by ve nipuncture on days 0, 3, and 36 to determine plasma cortisol, haptoglo bin, and the neutrophil:lymphocyte (N:L) ratio. A skin-fold thickness response to the mitogen phytohemagglutinin (PHA) was determined on day s 1 and 37. Gilts with a Yorkshire sire lay down less often (P < 0.05) , spent more time performing chain manipulation (P < 0.05) and drinker manipulation (P < 0.01) and tended to be more active (P < 0.13) than gilts with a Meishan sire. Furthermore, their plasma cortisol levels a nd N:L ratios were found to be lower (P < 0.01), suggesting genetic di fferences in adaptive abilities or strategies. Gilts in turn-around st alls stood more frequently, performed more nosing/licking of the stall bars, and more chain manipulation than gilts in conventional stalls ( P < 0.05). They also had a lower plasma cortisol level (P < 0.05). The percentage of time spent manipulating the chain increased from day 0 to day 7 (P < 0.05) and then remained constant throughout the experime nt. According to our data, providing stalled gilts with the opportunit y to turn increases certain activity levels and reduces plasma cortiso l level, but does not affect immune system functioning.